+.\" Copyright (c) 1991 Free Software Foundation -*-Text-*-
+.\" See section COPYING for conditions for redistribution
+.\" FIXME: no info here on predefines. Should there be? extra for C++...
+.TH CC 1 "28may1992" "GNU Tools" "GNU Tools"
+.de BP
+.sp
+.ti \-.2i
+\(**
+..
+.SH NAME
+cc, g++ \- GNU project C and C++ Compiler (v2 preliminary)
+.SH SYNOPSIS
+.RB cc " [" \c
+.IR option " | " filename " ].\|.\|.
+.br
+.RB g++ " [" \c
+.IR option " | " filename " ].\|.\|.
+.SH WARNING
+The information in this man page is an extract from the full
+documentation of the GNU C compiler, and is limited to the meaning of
+the options. This man page is not kept up to date except when
+volunteers want to maintain it.
+
+For complete and current documentation, refer to the Info file `\|\c
+.B gcc\c
+\&\|' or the manual
+.I
+Using and Porting GNU CC (for version 2.0)\c
+\&. Both are made from the Texinfo source file
+.BR gcc.texinfo .
+.SH DESCRIPTION
+The C and C++ compilers are integrated. Both process input files
+through one or more of four stages: preprocessing, compilation,
+assembly, and linking. Source filename suffixes identify the source
+language, but which name you use for the compiler governs default
+assumptions:
+.TP
+.B gcc
+assumes preprocessed (\c
+.B .i\c
+\&) files are C and assumes C style linking.
+.TP
+.B g++
+assumes preprocessed (\c
+.B .i\c
+\&) files are C++ and assumes C++ style linking.
+.PP
+Suffixes of source file names indicate the language and kind of
+processing to be done:
+
+.ta \w'.cxx 'u
+.B .c\c
+\& C source; preprocess, compile, assemble
+.br
+.B .C\c
+\& C++ source; preprocess, compile, assemble
+.br
+.B .cc\c
+\& C++ source; preprocess, compile, assemble
+.br
+.B .cxx\c
+\& C++ source; preprocess, compile, assemble
+.br
+.B .m\c
+\& Objective-C source; preprocess, compile, assemble
+.br
+.B .i\c
+\& preprocessed C; compile, assemble
+.br
+.B .ii\c
+\& preprocessed C++; compile, assemble
+.br
+.B .s\c
+\& Assembler source; assemble
+.br
+.B .S\c
+\& Assembler source; preprocess, assemble
+.br
+.B .h\c
+\& Preprocessor file; not usually named on command line
+
+.I ??\c
+\& Other (unrecognized) files passed to linker.
+.br
+\& Common cases:
+.br
+.B .o\c
+\& Object file
+.br
+.B .a\c
+\& Archive file
+
+Linking is always the last stage unless you use one of the
+.BR \-c ,
+.BR \-S ,
+or
+.B \-E
+options to avoid it (or unless compilation errors stop the whole
+process). For the link stage, all
+.B .o
+files corresponding to source files,
+.B \-l
+libraries, unrecognized filenames (including named
+.B .o
+object files and
+.B .a
+archives)
+are passed to the linker in command-line order.
+
+.SH OPTIONS
+Options must be separate: `\|\c
+.B \-dr\c
+\&\|' is quite different from `\|\c
+.B \-d \-r
+\&\|'.
+
+Most `\|\c
+.B \-f\c
+\&\|' and `\|\c
+.B \-W\c
+\&\|' options have two contrary forms:
+.BI \-f name
+and
+.BI \-fno\- name\c
+\& (or
+.BI \-W name
+and
+.BI \-Wno\- name\c
+\&). Only the non-default forms are shown here.
+
+Here is a summary of all the options, grouped by type. Explanations are
+in the following sections.
+
+.hy 0
+.na
+.TP
+.B Overall Options
+.br
+\-c
+\-S
+\-E
+.RI "\-o " file
+\-pipe
+\-v
+.RI "\-x " language
+
+.TP
+.B Language Options
+\-ansi
+\-fall\-virtual
+\-fcond\-mismatch
+\-fdollars\-in\-identifiers
+\-fenum\-int\-equiv
+\-fno\-asm
+\-fno\-builtin
+\-fno\-strict\-prototype
+\-fsigned\-bitfields
+\-fsigned\-char
+\-fthis\-is\-variable
+\-funsigned\-bitfields
+\-funsigned\-char
+\-fwritable\-strings
+\-traditional
+\-traditional\-cpp
+\-trigraphs
+
+.TP
+.B Warning Options
+\-fsyntax\-only
+\-pedantic
+\-pedantic\-errors
+\-w
+\-W
+\-Wall
+\-Waggregate\-return
+\-Wcast\-align
+\-Wcast\-qual
+\-Wcomment
+\-Wconversion
+\-Wenum\-clash
+\-Werror
+\-Wformat
+.RI \-Wid\-clash\- len
+\-Wimplicit
+\-Winline
+\-Wmissing\-prototypes
+\-Wparentheses
+\-Wpointer\-arith
+\-Wreturn\-type
+\-Wshadow
+\-Wstrict\-prototypes
+\-Wswitch
+\-Wtraditional
+\-Wtrigraphs
+\-Wuninitialized
+\-Wunused
+\-Wwrite\-strings
+
+.TP
+.B Debugging Options
+\-a
+.RI \-d letters
+\-fpretend\-float
+\-g
+\-gstabs
+\-gdwarf
+\-ggdb
+\-gsdb
+\-p
+\-pg
+\-save\-temps
+
+.TP
+.B Optimization Options
+\-fcaller\-saves
+\-fcse\-follow\-jumps
+\-fdelayed\-branch
+\-felide\-constructors
+\-fexpensive\-optimizations
+\-ffloat\-store
+\-fforce\-addr
+\-fforce\-mem
+\-finline
+\-finline\-functions
+\-fkeep\-inline\-functions
+\-fmemoize\-lookups
+\-fno\-default\-inline
+\-fno\-defer\-pop
+\-fno\-function\-cse
+\-fomit\-frame\-pointer
+\-frerun\-cse\-after\-loop
+\-fschedule\-insns
+\-fschedule\-insns2
+\-fstrength\-reduce
+\-fthread\-jumps
+\-funroll\-all\-loops
+\-funroll\-loops
+\-O
+\-O2
+
+.TP
+.B Preprocessor Options
+\-C
+\-dD
+\-dM
+\-dN
+.RI \-D macro [\|= defn \|]
+\-E
+\-H
+.RI "\-i " file
+\-M
+\-MD
+\-MM
+\-MMD
+\-nostdinc
+\-P
+.RI \-U macro
+\-undef
+
+.TP
+.B Linker Options
+.RI \-l library
+\-nostdlib
+\-static
+
+.TP
+.B Directory Options
+.RI \-B prefix
+.RI \-I dir
+\-I\-
+.RI \-L dir
+
+.TP
+.B Target Options
+.RI "\-b " machine
+.RI "\-V " version
+
+.TP
+.B Machine Dependent Options
+.I M680x0\ Options
+.br
+\-m68000
+\-m68020
+\-m68881
+\-mbitfield
+\-mc68000
+\-mc68020
+\-mfpa
+\-mnobitfield
+\-mrtd
+\-mshort
+\-msoft\-float
+
+.I VAX Options
+.br
+\-mg
+\-mgnu
+\-munix
+
+.I SPARC Options
+.br
+\-mfpu
+\-mno\-epilogue
+
+.I Convex Options
+.br
+\-margcount
+\-mc1
+\-mc2
+\-mnoargcount
+
+.I AMD29K Options
+.br
+\-m29000
+\-m29050
+\-mbw
+\-mdw
+\-mkernel\-registers
+\-mlarge
+\-mnbw
+\-mnodw
+\-msmall
+\-mstack\-check
+\-muser\-registers
+
+.I M88K Options
+.br
+\-mbig\-pic
+\-mcheck\-zero\-division
+\-mhandle\-large\-shift
+\-midentify\-revision
+\-mno\-check\-zero\-division
+\-mno\-ocs\-debug\-info
+\-mno\-ocs\-frame\-position
+\-mno\-optimize\-arg\-area
+\-mno\-underscores
+\-mocs\-debug\-info
+\-mocs\-frame\-position
+\-moptimize\-arg\-area
+.RI \-mshort\-data\- num
+\-msvr3
+\-msvr4
+\-mtrap\-large\-shift
+\-muse\-div\-instruction
+\-mversion\-03.00
+\-mwarn\-passed\-structs
+
+.I RS6000 Options
+.br
+\-mfp\-in\-toc
+\-mno\-fop\-in\-toc
+
+.I RT Options
+.br
+\-mcall\-lib\-mul
+\-mfp\-arg\-in\-fpregs
+\-mfp\-arg\-in\-gregs
+\-mfull\-fp\-blocks
+\-mhc\-struct\-return
+\-min\-line\-mul
+\-mminimum\-fp\-blocks
+\-mnohc\-struct\-return
+
+.I MIPS Options
+.br
+\-mcpu=\fIcpu type\fP
+\-mips2
+\-mips3
+\-mint64
+\-mlong64
+\-mlonglong128
+\-mmips\-as
+\-mgas
+\-mrnames
+\-mno\-rnames
+\-mgpopt
+\-mno\-gpopt
+\-mstats
+\-mno\-stats
+\-mmemcpy
+\-mno\-memcpy
+\-mno\-mips\-tfile
+\-mmips\-tfile
+\-msoft\-float
+\-mhard\-float
+\-mabicalls
+\-mno\-abicalls
+\-mhalf\-pic
+\-mno\-half\-pic
+\-G \fInum\fP
+
+.I i386 Options
+.br
+\-m486
+\-mno486
+\-msoft\-float
+
+.TP
+.B Code Generation Options
+.RI +e N
+.RI \-fcall\-saved\- reg
+.RI \-fcall\-used\- reg
+.RI \-ffixed\- reg
+\-fno\-common
+\-fno\-gnu\-binutils
+\-fnonnull\-objects
+\-fpcc\-struct\-return
+\-fpic
+\-fPIC
+\-fshared\-data
+\-fshort\-enums
+\-fshort\-double
+\-fvolatile
+.ad b
+.hy 1
+
+.SH OVERALL OPTIONS
+.TP
+.BI "\-x " "language"
+Specify explicitly the
+.I language\c
+\& for the following input files (rather than choosing a default based
+on the file name suffix) . This option applies to all following input
+files until the next `\|\c
+.B \-x\c
+\&\|' option. Possible values of \c
+.I language\c
+\& are
+`\|\c
+.B c\c
+\&\|', `\|\c
+.B objective\-c\c
+\&\|', `\|\c
+.B c\-header\c
+\&\|', `\|\c
+.B c++\c
+\&\|',
+`\|\c
+.B cpp\-output\c
+\&\|', `\|\c
+.B assembler\c
+\&\|', and `\|\c
+.B assembler\-with\-cpp\c
+\&\|'.
+.TP
+.B \-x none
+Turn off any specification of a language, so that subsequent files are
+handled according to their file name suffixes (as they are if `\|\c
+.B \-x\c
+\&\|'
+has not been used at all).
+.PP
+
+If you want only some of the four stages (preprocess, compile,
+assemble, link), you can use
+`\|\c
+.B \-x\c
+\&\|' (or filename suffixes) to tell \c
+.B gcc\c
+\& where to start, and
+one of the options `\|\c
+.B \-c\c
+\&\|', `\|\c
+.B \-S\c
+\&\|', or `\|\c
+.B \-E\c
+\&\|' to say where
+\c
+.B gcc\c
+\& is to stop. Note that some combinations (for example,
+`\|\c
+.B \-x cpp\-output \-E\c
+\&\|') instruct \c
+.B gcc\c
+\& to do nothing at all.
+.TP
+.B \-c
+Compile or assemble the source files, but do not link. The compiler
+output is an object file corresponding to each source file.
+
+By default, GCC makes the object file name for a source file by replacing
+the suffix `\|\c
+.B .c\c
+\&\|', `\|\c
+.B .i\c
+\&\|', `\|\c
+.B .s\c
+\&\|', etc., with `\|\c
+.B .o\c
+\&\|'. Use
+.B \-o\c
+\& to select another name.
+
+GCC ignores any unrecognized input files (those that do not require
+compilation or assembly) with the
+.B \-c
+option.
+.TP
+.B \-S
+Stop after the stage of compilation proper; do not assemble. The output
+is an assembler code file for each non-assembler input
+file specified.
+
+By default, GCC makes the assembler file name for a source file by
+replacing the suffix `\|\c
+.B .c\c
+\&\|', `\|\c
+.B .i\c
+\&\|', etc., with `\|\c
+.B .s\c
+\&\|'. Use
+.B \-o\c
+\& to select another name.
+
+
+GCC ignores any input files that don't require compilation.
+.TP
+.B \-E
+Stop after the preprocessing stage; do not run the compiler proper. The
+output is preprocessed source code, which is sent to the
+standard output.
+
+GCC ignores input files which don't require preprocessing.
+.TP
+.BI "\-o " file\c
+\&
+Place output in file \c
+.I file\c
+\&. This applies to whatever
+sort of output GCC is producing, whether it be an executable file,
+an object file, an assembler file or preprocessed C code.
+
+Since only one output file can be specified, it does not make sense to
+use `\|\c
+.B \-o\c
+\&\|' when compiling more than one input file, unless you are
+producing an executable file as output.
+
+If you do not specify `\|\c
+.B \-o\c
+\&\|', the default is to put an executable file
+in `\|\c
+.B a.out\c
+\&\|', an object file for `\|\c
+.B \c
+.I source\c
+\&.\c
+.I suffix\c
+\&\c
+\&\|' in
+`\|\c
+.B \c
+.I source\c
+\&.o\c
+\&\|', its assembler file in `\|\c
+.B \c
+.I source\c
+\&.s\c
+\&\|', and
+all preprocessed C source on the standard output.
+.TP
+.B \-v
+Print (on the standard error output) the commands executed to run the stages
+of compilation. Also print the version number of the compiler driver
+program and of the preprocessor and the compiler proper.
+.TP
+.B \-pipe
+Use pipes rather than temporary files for communication between the
+various stages of compilation. This fails to work on some systems where
+the assembler cannot read from a pipe; but the GNU assembler has
+no trouble.
+.PP
+
+.SH LANGUAGE OPTIONS
+The following options control the dialect of C that the compiler
+accepts:
+.TP
+.B \-ansi
+.I
+Support all ANSI standard C programs.
+.I
+
+This turns off certain features of GNU C that are incompatible with
+ANSI C, such as the \c
+.B asm\c
+\&, \c
+.B inline\c
+\& and \c
+.B typeof\c
+\&
+keywords, and predefined macros such as \c
+.B unix\c
+\& and \c
+.B vax\c
+\&
+that identify the type of system you are using. It also enables the
+undesirable and rarely used ANSI trigraph feature, and makes the
+preprocessor accept `\|\c
+.B $\c
+\&\|' as part of identifiers.
+
+The alternate keywords \c
+.B __asm__\c
+\&, \c
+.B __extension__\c
+\&,
+\c
+.B __inline__\c
+\& and \c
+.B __typeof__\c
+\& continue to work despite
+`\|\c
+.B \-ansi\c
+\&\|'. You would not want to use them in an ANSI C program, of
+course, but it is useful to put them in header files that might be included
+in compilations done with `\|\c
+.B \-ansi\c
+\&\|'. Alternate predefined macros
+such as \c
+.B __unix__\c
+\& and \c
+.B __vax__\c
+\& are also available, with or
+without `\|\c
+.B \-ansi\c
+\&\|'.
+
+The `\|\c
+.B \-ansi\c
+\&\|' option does not cause non-ANSI programs to be
+rejected gratuitously. For that, `\|\c
+.B \-pedantic\c
+\&\|' is required in
+addition to `\|\c
+.B \-ansi\c
+\&\|'.
+
+The preprocessor predefines a macro \c
+.B __STRICT_ANSI__\c
+\& when you use the `\|\c
+.B \-ansi\c
+\&\|'
+option. Some header files may notice this macro and refrain
+from declaring certain functions or defining certain macros that the
+ANSI standard doesn't call for; this is to avoid interfering with any
+programs that might use these names for other things.
+.TP
+.B \-fno\-asm
+Do not recognize \c
+.B asm\c
+\&, \c
+.B inline\c
+\& or \c
+.B typeof\c
+\& as a
+keyword. These words may then be used as identifiers. You can
+use \c
+.B __asm__\c
+\&, \c
+.B __inline__\c
+\& and \c
+.B __typeof__\c
+\& instead.
+`\|\c
+.B \-ansi\c
+\&\|' implies `\|\c
+.B \-fno\-asm\c
+\&\|'.
+.TP
+.B \-fno\-builtin
+.I (Ignored for C++.)
+Don't recognize non-ANSI built-in functions. `\|\c
+.B \-ansi\c
+\&\|' also has this
+effect. Currently, the only function affected is
+.B alloca\c
+\&.
+.TP
+.B \-fno\-strict\-prototype
+.I
+(C++ only.)
+Consider the declaration \c
+.B int foo ();\c
+\&. In C++, this means that the
+function \c
+.B foo\c
+\& takes no arguments. In ANSI C, this is declared
+.B int foo(void);\c
+\&. With the flag `\|\c
+.B \-fno\-strict\-prototype\c
+\&\|',
+declaring functions with no arguments is equivalent to declaring its
+argument list to be untyped, i.e., \c
+.B int foo ();\c
+\& is equivalent to
+saying \c
+.B int foo (...);\c
+\&.
+.TP
+.B \-trigraphs
+Support ANSI C trigraphs. The `\|\c
+.B \-ansi\c
+\&\|' option implies `\|\c
+.B \-trigraphs\c
+\&\|'.
+.TP
+.B \-traditional
+Attempt to support some aspects of traditional C compilers.
+For details, see the GNU C Manual; the duplicate list here
+has been deleted so that we won't get complaints when it
+is out of date.
+
+But one note about C++ programs only (not C). `\|\c
+.B \-traditional\c
+\&\|' has one additional effect for C++: assignment to
+.B this
+is permitted. This is the same as the effect of `\|\c
+.B \-fthis\-is\-variable\c
+\&\|'.
+.TP
+.B \-traditional\-cpp
+Attempt to support some aspects of traditional C preprocessors.
+This includes the items that specifically mention the preprocessor above,
+but none of the other effects of `\|\c
+.B \-traditional\c
+\&\|'.
+.TP
+.B \-fdollars\-in\-identifiers
+.I
+(C++ only.)
+Permit the use of `\|\c
+.B $\c
+\&\|' in identifiers. (For GNU C, this is the default, and you can
+forbid it with `\|\c
+.B \-ansi\c
+\&\|'.)
+Traditional C allowed the character `\|\c
+.B $\c
+\&\|' to form part of identifiers; by default, GNU C also
+allows this. However, ANSI C forbids `\|\c
+.B $\c
+\&\|' in identifiers, and GNU C++ also forbids it by default on most
+platforms (though on some platforms it's enabled by default for GNU
+C++ as well).
+.TP
+.B \-fenum\-int\-equiv
+.I
+(C++ only.)
+Normally GNU C++ allows conversion of
+.B enum
+to
+.B int\c
+\&, but not the other way around. Use this option if you want GNU C++
+to allow conversion of
+.B int
+to
+.B enum
+as well.
+.TP
+.B \-fall\-virtual
+.I
+(C++ only.)
+When you use the `\|\c
+.B \-fall\-virtual\c
+\&\|', all member functions
+(except for constructor functions and new/delete member operators)
+declared in the same class with a ``method-call'' operator method are
+treated as virtual functions of the given class. In effect, all
+of these methods become ``implicitly virtual.''
+
+This does \c
+.I not\c
+\& mean that all calls to these methods will be made through the
+internal table of virtual functions. There are some circumstances
+under which it is obvious that a call to a given virtual function can
+be made directly, and in these cases the calls still go direct.
+
+The effect of making all methods of a class with a declared
+\&`\|\c
+.B
+operator->()()\c
+\&\|' implicitly virtual using `\|\c
+.B \-fall\-virtual\c
+\&\|' extends
+also to all non-constructor methods of any class derived from such a
+class.
+.TP
+.B \-fcond\-mismatch
+Allow conditional expressions with mismatched types in the second and
+third arguments. The value of such an expression is void.
+.TP
+.B \-fthis\-is\-variable
+.I
+(C++ only.)
+The incorporation of user-defined free store management into C++ has
+made assignment to \c
+.B this\c
+\& an anachronism. Therefore, by default GNU
+C++ treats the type of \c
+.B this\c
+\& in a member function of \c
+.B class X\c
+\&
+to be \c
+.B X *const\c
+\&. In other words, it is illegal to assign to
+\c
+.B this\c
+\& within a class member function. However, for backwards
+compatibility, you can invoke the old behavior by using
+\&`\|\c
+.B \-fthis\-is\-variable\c
+\&\|'.
+.TP
+.B \-funsigned\-char
+Let the type \c
+.B char\c
+\& be unsigned, like \c
+.B unsigned char\c
+\&.
+
+Each kind of machine has a default for what \c
+.B char\c
+\& should
+be. It is either like \c
+.B unsigned char\c
+\& by default or like
+\c
+.B signed char\c
+\& by default.
+
+Ideally, a portable program should always use \c
+.B signed char\c
+\& or
+\c
+.B unsigned char\c
+\& when it depends on the signedness of an object.
+But many programs have been written to use plain \c
+.B char\c
+\& and
+expect it to be signed, or expect it to be unsigned, depending on the
+machines they were written for. This option, and its inverse, let you
+make such a program work with the opposite default.
+
+The type \c
+.B char\c
+\& is always a distinct type from each of
+\c
+.B signed char\c
+\& and \c
+.B unsigned char\c
+\&, even though its behavior
+is always just like one of those two.
+
+.TP
+.B \-fsigned\-char
+Let the type \c
+.B char\c
+\& be signed, like \c
+.B signed char\c
+\&.
+
+Note that this is equivalent to `\|\c
+.B \-fno\-unsigned\-char\c
+\&\|', which is
+the negative form of `\|\c
+.B \-funsigned\-char\c
+\&\|'. Likewise,
+`\|\c
+.B \-fno\-signed\-char\c
+\&\|' is equivalent to `\|\c
+.B \-funsigned\-char\c
+\&\|'.
+.TP
+.B \-fsigned\-bitfields
+.TP
+.B \-funsigned\-bitfields
+.TP
+.B \-fno\-signed\-bitfields
+.TP
+.B \-fno\-unsigned\-bitfields
+These options control whether a bitfield is
+signed or unsigned, when declared with no explicit `\|\c
+.B signed\c
+\&\|' or `\|\c
+.B unsigned\c
+\&\|' qualifier. By default, such a bitfield is
+signed, because this is consistent: the basic integer types such as
+\c
+.B int\c
+\& are signed types.
+
+However, when you specify `\|\c
+.B \-traditional\c
+\&\|', bitfields are all unsigned
+no matter what.
+.TP
+.B \-fwritable\-strings
+Store string constants in the writable data segment and don't uniquize
+them. This is for compatibility with old programs which assume they
+can write into string constants. `\|\c
+.B \-traditional\c
+\&\|' also has this
+effect.
+
+Writing into string constants is a very bad idea; ``constants'' should
+be constant.
+.PP
+
+.SH PREPROCESSOR OPTIONS
+These options control the C preprocessor, which is run on each C source
+file before actual compilation.
+
+If you use the `\|\c
+.B \-E\c
+\&\|' option, GCC does nothing except preprocessing.
+Some of these options make sense only together with `\|\c
+.B \-E\c
+\&\|' because
+they cause the preprocessor output to be unsuitable for actual
+compilation.
+.TP
+.BI "\-i " file\c
+\&
+Process \c
+.I file\c
+\& as input, discarding the resulting output, before
+processing the regular input file. Because the output generated from
+\c
+.I file\c
+\& is discarded, the only effect of `\|\c
+.B \-i \c
+.I file\c
+\&\c
+\&\|' is to
+make the macros defined in \c
+.I file\c
+\& available for use in the main
+input. The preprocessor evaluates any `\|\c
+.B \-D\c
+\&\|' and `\|\c
+.B \-U\c
+\&\|' options
+on the command line before processing `\|\c
+.B \-i\c
+\&\|' \c
+.I file\c
+\&.
+.TP
+.B \-nostdinc
+Do not search the standard system directories for header files. Only
+the directories you have specified with `\|\c
+.B \-I\c
+\&\|' options (and the
+current directory, if appropriate) are searched.
+
+By using both `\|\c
+.B \-nostdinc\c
+\&\|' and `\|\c
+.B \-I\-\c
+\&\|', you can limit the include-file search file to only those
+directories you specify explicitly.
+.TP
+.B \-undef
+Do not predefine any nonstandard macros. (Including architecture flags).
+.TP
+.B \-E
+Run only the C preprocessor. Preprocess all the C source files
+specified and output the results to the standard output or to the
+specified output file.
+.TP
+.B \-C
+Tell the preprocessor not to discard comments. Used with the
+`\|\c
+.B \-E\c
+\&\|' option.
+.TP
+.B \-P
+Tell the preprocessor not to generate `\|\c
+.B #line\c
+\&\|' commands.
+Used with the `\|\c
+.B \-E\c
+\&\|' option.
+.TP
+.B \-M
+Tell the preprocessor to output a rule suitable for \c
+.B make\c
+\&
+describing the dependencies of each object file. For each source file,
+the preprocessor outputs one \c
+.B make\c
+\&-rule whose target is the object
+file name for that source file and whose dependencies are all the files
+`\|\c
+.B #include\c
+\&\|'d in it. This rule may be a single line or may be
+continued with `\|\c
+.B \e\c
+\&\|newline if it is long. The list of rules is
+printed on the standard output instead of the preprocessed C program.
+
+`\|\c
+.B \-M\c
+\&\|' implies `\|\c
+.B \-E\c
+\&\|'.
+.TP
+.B \-MM
+Like `\|\c
+.B \-M\c
+\&\|' but the output mentions only the user header files
+included with `\|\c
+.B #include "\c
+.I file\c
+\&"\c
+\&\|'. System header files
+included with `\|\c
+.B #include <\c
+.I file\c
+\&>\c
+\&\|' are omitted.
+.TP
+.B \-MD
+Like `\|\c
+.B \-M\c
+\&\|' but the dependency information is written to files with
+names made by replacing `\|\c
+.B .c\c
+\&\|' with `\|\c
+.B .d\c
+\&\|' at the end of the
+input file names. This is in addition to compiling the file as
+specified\(em\&`\|\c
+.B \-MD\c
+\&\|' does not inhibit ordinary compilation the way
+`\|\c
+.B \-M\c
+\&\|' does.
+
+The Mach utility `\|\c
+.B md\c
+\&\|' can be used to merge the `\|\c
+.B .d\c
+\&\|' files
+into a single dependency file suitable for using with the `\|\c
+.B make\c
+\&\|'
+command.
+.TP
+.B \-MMD
+Like `\|\c
+.B \-MD\c
+\&\|' except mention only user header files, not system
+header files.
+.TP
+.B \-H
+Print the name of each header file used, in addition to other normal
+activities.
+.TP
+.BI \-D macro
+Define macro \c
+.I macro\c
+\& with the string `\|\c
+.B 1\c
+\&\|' as its definition.
+.TP
+.BI \-D macro = defn
+Define macro \c
+.I macro\c
+\& as \c
+.I defn\c
+\&. All instances of `\|\c
+.B \-D\c
+\&\|' on
+the command line are processed before any `\|\c
+.B \-U\c
+\&\|' or `\|\c
+.B \-i\c
+\&\|' options.
+.TP
+.BI \-U macro
+Undefine macro \c
+.I macro\c
+\&. `\|\c
+.B \-U\c
+\&\|' options are evaluated after all `\|\c
+.B \-D\c
+\&\|' options, but before any `\|\c
+.B \-i\c
+\&\|' options.
+.TP
+.B \-dM
+Tell the preprocessor to output only a list of the macro definitions
+that are in effect at the end of preprocessing. Used with the `\|\c
+.B \-E\c
+\&\|'
+option.
+.TP
+.B \-dD
+Tell the preprocessing to pass all macro definitions into the output, in
+their proper sequence in the rest of the output.
+.TP
+.B \-dN
+Like `\|\c
+.B \-dD\c
+\&\|' except that the macro arguments and contents are omitted.
+Only `\|\c
+.B #define \c
+.I name\c
+\&\c
+\&\|' is included in the output.
+.PP
+
+.SH LINKER OPTIONS
+These options come into play when the compiler links object files into
+an executable output file. They are meaningless if the compiler is
+not doing a link step.
+.TP
+.I object-file-name
+A file name that does not end in a special recognized suffix is
+considered to name an object file or library. (Object files are
+distinguished from libraries by the linker according to the file
+contents.) If GCC does a link step, these object files are used as input
+to the linker.
+.TP
+.BI \-l library\c
+\&
+Use the library named \c
+.I library\c
+\& when linking.
+
+The linker searches a standard list of directories for the library,
+which is actually a file named `\|\c
+.B lib\c
+.I library\c
+\&.a\c
+\&\|'. The linker
+then uses this file as if it had been specified precisely by name.
+
+The directories searched include several standard system directories
+plus any that you specify with `\|\c
+.B \-L\c
+\&\|'.
+
+Normally the files found this way are library files\(em\&archive files
+whose members are object files. The linker handles an archive file by
+scanning through it for members which define symbols that have so far
+been referenced but not defined. However, if the linker finds an
+ordinary object file rather than a library, the object file is linked
+in the usual fashion. The only difference between using an `\|\c
+.B \-l\c
+\&\|' option and specifying a file
+name is that `\|\c
+.B \-l\c
+\&\|' surrounds
+.I library
+with `\|\c
+.B lib\c
+\&\|' and `\|\c
+.B .a\c
+\&\|' and searches several directories.
+.TP
+.B \-nostdlib
+Don't use the standard system libraries and startup files when linking.
+Only the files you specify will be passed to the linker.
+.TP
+.B \-static
+On systems that support dynamic linking, this prevents linking with the shared
+libraries. On other systems, this option has no effect.
+.PP
+
+.SH DIRECTORY OPTIONS
+These options specify directories to search for header files, for
+libraries and for parts of the compiler:
+.TP
+.BI "\-I" "dir"\c
+\&
+Append directory \c
+.I dir\c
+\& to the list of directories searched for include files.
+.TP
+.B \-I\-
+Any directories you specify with `\|\c
+.B \-I\c
+\&\|' options before the `\|\c
+.B \-I\-\c
+\&\|'
+option are searched only for the case of `\|\c
+.B
+#include "\c
+.I file\c
+.B
+\&"\c
+\&\|';
+they are not searched for `\|\c
+.B #include <\c
+.I file\c
+\&>\c
+\&\|'.
+
+If additional directories are specified with `\|\c
+.B \-I\c
+\&\|' options after
+the `\|\c
+.B \-I\-\c
+\&\|', these directories are searched for all `\|\c
+.B #include\c
+\&\|'
+directives. (Ordinarily \c
+.I all\c
+\& `\|\c
+.B \-I\c
+\&\|' directories are used
+this way.)
+
+In addition, the `\|\c
+.B \-I\-\c
+\&\|' option inhibits the use of the current
+directory (where the current input file came from) as the first search
+directory for `\|\c
+.B
+#include "\c
+.I file\c
+.B
+\&"\c
+\&\|'. There is no way to
+override this effect of `\|\c
+.B \-I\-\c
+\&\|'. With `\|\c
+.B \-I.\c
+\&\|' you can specify
+searching the directory which was current when the compiler was
+invoked. That is not exactly the same as what the preprocessor does
+by default, but it is often satisfactory.
+
+`\|\c
+.B \-I\-\c
+\&\|' does not inhibit the use of the standard system directories
+for header files. Thus, `\|\c
+.B \-I\-\c
+\&\|' and `\|\c
+.B \-nostdinc\c
+\&\|' are
+independent.
+.TP
+.BI "\-L" "dir"\c
+\&
+Add directory \c
+.I dir\c
+\& to the list of directories to be searched
+for `\|\c
+.B \-l\c
+\&\|'.
+.TP
+.BI "\-B" "prefix"\c
+\&
+This option specifies where to find the executables, libraries and
+data files of the compiler itself.
+
+The compiler driver program runs one or more of the subprograms
+`\|\c
+.B cpp\c
+\&\|', `\|\c
+.B cc1\c
+\&\|' (or, for C++, `\|\c
+.B cc1plus\c
+\&\|'), `\|\c
+.B as\c
+\&\|' and `\|\c
+.B ld\c
+\&\|'. It tries
+\c
+.I prefix\c
+\& as a prefix for each program it tries to run, both with and
+without `\|\c
+.B \c
+.I machine\c
+\&/\c
+.I version\c
+\&/\c
+\&\|'.
+
+For each subprogram to be run, the compiler driver first tries the
+`\|\c
+.B \-B\c
+\&\|' prefix, if any. If that name is not found, or if `\|\c
+.B \-B\c
+\&\|'
+was not specified, the driver tries two standard prefixes, which are
+`\|\c
+.B /usr/lib/gcc/\c
+\&\|' and `\|\c
+.B /usr/local/lib/gcc-lib/\c
+\&\|'. If neither of
+those results in a file name that is found, the compiler driver
+searches for the unmodified program
+name, using the directories specified in your
+`\|\c
+.B PATH\c
+\&\|' environment variable.
+
+The run-time support file `\|\c
+.B libgcc.a\c
+\&\|' is also searched for using the
+`\|\c
+.B \-B\c
+\&\|' prefix, if needed. If it is not found there, the two
+standard prefixes above are tried, and that is all. The file is left
+out of the link if it is not found by those means. Most of the time,
+on most machines, `\|\c
+.B libgcc.a\c
+\&\|' is not actually necessary.
+
+You can get a similar result from the environment variable
+\c
+.B GCC_EXEC_PREFIX\c
+\&; if it is defined, its value is used as a prefix
+in the same way. If both the `\|\c
+.B \-B\c
+\&\|' option and the
+\c
+.B GCC_EXEC_PREFIX\c
+\& variable are present, the `\|\c
+.B \-B\c
+\&\|' option is
+used first and the environment variable value second.
+.PP
+
+.SH WARNING OPTIONS
+Warnings are diagnostic messages that report constructions which
+are not inherently erroneous but which are risky or suggest there
+may have been an error.
+
+These options control the amount and kinds of warnings produced by GNU
+CC:
+.TP
+.B \-fsyntax\-only
+Check the code for syntax errors, but don't emit any output.
+.TP
+.B \-w
+Inhibit all warning messages.
+.TP
+.B \-pedantic
+Issue all the warnings demanded by strict ANSI standard C; reject
+all programs that use forbidden extensions.
+
+Valid ANSI standard C programs should compile properly with or without
+this option (though a rare few will require `\|\c
+.B \-ansi\c
+\&\|'). However,
+without this option, certain GNU extensions and traditional C features
+are supported as well. With this option, they are rejected. There is
+no reason to \c
+.I use\c
+\& this option; it exists only to satisfy pedants.
+
+`\|\c
+.B \-pedantic\c
+\&\|' does not cause warning messages for use of the
+alternate keywords whose names begin and end with `\|\c
+.B __\c
+\&\|'. Pedantic
+warnings are also disabled in the expression that follows
+\c
+.B __extension__\c
+\&. However, only system header files should use
+these escape routes; application programs should avoid them.
+.TP
+.B \-pedantic\-errors
+Like `\|\c
+.B \-pedantic\c
+\&\|', except that errors are produced rather than
+warnings.
+.TP
+.B \-W
+Print extra warning messages for these events:
+.TP
+\ \ \ \(bu
+A nonvolatile automatic variable might be changed by a call to
+\c
+.B longjmp\c
+\&. These warnings are possible only in
+optimizing compilation.
+
+The compiler sees only the calls to \c
+.B setjmp\c
+\&. It cannot know
+where \c
+.B longjmp\c
+\& will be called; in fact, a signal handler could
+call it at any point in the code. As a result, you may get a warning
+even when there is in fact no problem because \c
+.B longjmp\c
+\& cannot
+in fact be called at the place which would cause a problem.
+.TP
+\ \ \ \(bu
+A function can return either with or without a value. (Falling
+off the end of the function body is considered returning without
+a value.) For example, this function would evoke such a
+warning:
+.sp
+.br
+foo\ (a)
+.br
+{
+.br
+\ \ if\ (a\ >\ 0)
+.br
+\ \ \ \ return\ a;
+.br
+}
+.br
+.sp
+
+Spurious warnings can occur because GNU CC does not realize that
+certain functions (including \c
+.B abort\c
+\& and \c
+.B longjmp\c
+\&)
+will never return.
+.TP
+\ \ \ \(bu
+An expression-statement contains no side effects.
+.TP
+\ \ \ \(bu
+An unsigned value is compared against zero with `\|\c
+.B >\c
+\&\|' or `\|\c
+.B <=\c
+\&\|'.
+.PP
+.TP
+.B \-Wimplicit
+Warn whenever a function or parameter is implicitly declared.
+.TP
+.B \-Wreturn\-type
+Warn whenever a function is defined with a return-type that defaults
+to \c
+.B int\c
+\&. Also warn about any \c
+.B return\c
+\& statement with no
+return-value in a function whose return-type is not \c
+.B void\c
+\&.
+.TP
+.B \-Wunused
+Warn whenever a local variable is unused aside from its declaration,
+whenever a function is declared static but never defined, and whenever
+a statement computes a result that is explicitly not used.
+.TP
+.B \-Wswitch
+Warn whenever a \c
+.B switch\c
+\& statement has an index of enumeral type
+and lacks a \c
+.B case\c
+\& for one or more of the named codes of that
+enumeration. (The presence of a \c
+.B default\c
+\& label prevents this
+warning.) \c
+.B case\c
+\& labels outside the enumeration range also
+provoke warnings when this option is used.
+.TP
+.B \-Wcomment
+Warn whenever a comment-start sequence `\|\c
+.B /*\c
+\&\|' appears in a comment.
+.TP
+.B \-Wtrigraphs
+Warn if any trigraphs are encountered (assuming they are enabled).
+.TP
+.B \-Wformat
+Check calls to \c
+.B printf\c
+\& and \c
+.B scanf\c
+\&, etc., to make sure that
+the arguments supplied have types appropriate to the format string
+specified.
+.TP
+.B \-Wuninitialized
+An automatic variable is used without first being initialized.
+
+These warnings are possible only in optimizing compilation,
+because they require data flow information that is computed only
+when optimizing. If you don't specify `\|\c
+.B \-O\c
+\&\|', you simply won't
+get these warnings.
+
+These warnings occur only for variables that are candidates for
+register allocation. Therefore, they do not occur for a variable that
+is declared \c
+.B volatile\c
+\&, or whose address is taken, or whose size
+is other than 1, 2, 4 or 8 bytes. Also, they do not occur for
+structures, unions or arrays, even when they are in registers.
+
+Note that there may be no warning about a variable that is used only
+to compute a value that itself is never used, because such
+computations may be deleted by data flow analysis before the warnings
+are printed.
+
+These warnings are made optional because GNU CC is not smart
+enough to see all the reasons why the code might be correct
+despite appearing to have an error. Here is one example of how
+this can happen:
+
+.sp
+.br
+{
+.br
+\ \ int\ x;
+.br
+\ \ switch\ (y)
+.br
+\ \ \ \ {
+.br
+\ \ \ \ case\ 1:\ x\ =\ 1;
+.br
+\ \ \ \ \ \ break;
+.br
+\ \ \ \ case\ 2:\ x\ =\ 4;
+.br
+\ \ \ \ \ \ break;
+.br
+\ \ \ \ case\ 3:\ x\ =\ 5;
+.br
+\ \ \ \ }
+.br
+\ \ foo\ (x);
+.br
+}
+.br
+.sp
+
+
+If the value of \c
+.B y\c
+\& is always 1, 2 or 3, then \c
+.B x\c
+\& is
+always initialized, but GNU CC doesn't know this. Here is
+another common case:
+
+.sp
+.br
+{
+.br
+\ \ int\ save_y;
+.br
+\ \ if\ (change_y)\ save_y\ =\ y,\ y\ =\ new_y;
+.br
+\ \ .\|.\|.
+.br
+\ \ if\ (change_y)\ y\ =\ save_y;
+.br
+}
+.br
+.sp
+
+
+This has no bug because \c
+.B save_y\c
+\& is used only if it is set.
+
+Some spurious warnings can be avoided if you declare as
+\c
+.B volatile\c
+\& all the functions you use that never return.
+.TP
+.B \-Wparentheses
+Warn if parentheses are omitted in certain contexts.
+.TP
+.B \-Wall
+All of the above `\|\c
+.B \-W\c
+\&\|' options combined. These are all the
+options which pertain to usage that we recommend avoiding and that we
+believe are easy to avoid, even in conjunction with macros.
+.PP
+
+The remaining `\|\c
+.B \-W.\|.\|.\c
+\&\|' options are not implied by `\|\c
+.B \-Wall\c
+\&\|'
+because they warn about constructions that we consider reasonable to
+use, on occasion, in clean programs.
+.TP
+.B \-Wtraditional
+Warn about certain constructs that behave differently in traditional and
+ANSI C.
+.TP
+\ \ \ \(bu
+Macro arguments occurring within string constants in the macro body.
+These would substitute the argument in traditional C, but are part of
+the constant in ANSI C.
+.TP
+\ \ \ \(bu
+A function declared external in one block and then used after the end of
+the block.
+.TP
+\ \ \ \(bu
+A \c
+.B switch\c
+\& statement has an operand of type \c
+.B long\c
+\&.
+.PP
+.TP
+.B \-Wshadow
+Warn whenever a local variable shadows another local variable.
+.TP
+.BI "\-Wid\-clash\-" "len"\c
+\&
+Warn whenever two distinct identifiers match in the first \c
+.I len\c
+\&
+characters. This may help you prepare a program that will compile
+with certain obsolete, brain-damaged compilers.
+.TP
+.B \-Wpointer\-arith
+Warn about anything that depends on the ``size of'' a function type or
+of \c
+.B void\c
+\&. GNU C assigns these types a size of 1, for
+convenience in calculations with \c
+.B void *\c
+\& pointers and pointers
+to functions.
+.TP
+.B \-Wcast\-qual
+Warn whenever a pointer is cast so as to remove a type qualifier from
+the target type. For example, warn if a \c
+.B const char *\c
+\& is cast
+to an ordinary \c
+.B char *\c
+\&.
+.TP
+.B \-Wcast\-align
+Warn whenever a pointer is cast such that the required alignment of the
+target is increased. For example, warn if a \c
+.B char *\c
+\& is cast to
+an \c
+.B int *\c
+\& on machines where integers can only be accessed at
+two- or four-byte boundaries.
+.TP
+.B \-Wwrite\-strings
+Give string constants the type \c
+.B const char[\c
+.I length\c
+\&]\c
+\& so that
+copying the address of one into a non-\c
+.B const\c
+\& \c
+.B char *\c
+\&
+pointer will get a warning. These warnings will help you find at
+compile time code that can try to write into a string constant, but
+only if you have been very careful about using \c
+.B const\c
+\& in
+declarations and prototypes. Otherwise, it will just be a nuisance;
+this is why we did not make `\|\c
+.B \-Wall\c
+\&\|' request these warnings.
+.TP
+.B \-Wconversion
+Warn if a prototype causes a type conversion that is different from what
+would happen to the same argument in the absence of a prototype. This
+includes conversions of fixed point to floating and vice versa, and
+conversions changing the width or signedness of a fixed point argument
+except when the same as the default promotion.
+.TP
+.B \-Waggregate\-return
+Warn if any functions that return structures or unions are defined or
+called. (In languages where you can return an array, this also elicits
+a warning.)
+.TP
+.B \-Wstrict\-prototypes
+Warn if a function is declared or defined without specifying the
+argument types. (An old-style function definition is permitted without
+a warning if preceded by a declaration which specifies the argument
+types.)
+.TP
+.B \-Wmissing\-prototypes
+Warn if a global function is defined without a previous prototype
+declaration. This warning is issued even if the definition itself
+provides a prototype. The aim is to detect global functions that fail
+to be declared in header files.
+.TP
+.B \-Wenum\-clash
+.I (C++ only.)
+Warn when converting between different enumeration types.
+.TP
+.B \-Woverloaded\-virtual
+.I (C++ only.)
+In a derived class, the definitions of virtual functions must match
+the type signature of a virtual function declared in the base class.
+Use this option to request warnings when a derived class declares a
+function that may be an erroneous attempt to define a virtual
+function: that is, warn when a function with the same name as a
+virtual function in the base class, but with a type signature that
+doesn't match any virtual functions from the base class.
+.TP
+.B \-Winline
+Warn if a function can not be inlined, and either it was declared as inline,
+or else the
+.B \-finline\-functions
+option was given.
+.TP
+.B \-Werror
+Treat warnings as errors; abort compilation after any warning.
+.PP
+
+.SH DEBUGGING OPTIONS
+GNU CC has various special options that are used for debugging
+either your program or GCC:
+.TP
+.B \-g
+Produce debugging information in the operating system's native format
+(for DBX or SDB or DWARF). GDB also can work with this debugging
+information. On most systems that use DBX format, `\|\c
+.B \-g\c
+\&\|' enables use
+of extra debugging information that only GDB can use; if you want to
+control for certain whether to generate this information, use
+`\|\c
+.B \-ggdb\c
+\&\|' or `\|\c
+.B \-gdbx\c
+\&\|'.
+
+Unlike most other C compilers, GNU CC allows you to use `\|\c
+.B \-g\c
+\&\|' with
+`\|\c
+.B \-O\c
+\&\|'. The shortcuts taken by optimized code may occasionally
+produce surprising results: some variables you declared may not exist
+at all; flow of control may briefly move where you did not expect it;
+some statements may not be executed because they compute constant
+results or their values were already at hand; some statements may
+execute in different places because they were moved out of loops.
+
+Nevertheless it proves possible to debug optimized output. This makes
+it reasonable to use the optimizer for programs that might have bugs.
+
+The following options are useful when GNU CC is configured and
+compiled with the capability for more than one debugging format.
+.TP
+.B \-ggdb
+Produce debugging information in DBX format (if that is supported),
+including GDB extensions.
+.TP
+.B \-gdbx
+Produce debugging information in DBX format (if that is supported),
+without GDB extensions.
+.TP
+.B \-gsdb
+Produce debugging information in SDB format (if that is supported).
+.TP
+.B \-gdwarf
+Produce debugging information in DWARF format (if that is supported).
+.PP
+.BI "\-g" "level"
+.br
+.BI "\-ggdb" "level"
+.br
+.BI "\-gdbx" "level"
+.br
+.BI "\-gsdb" "level"
+.TP
+.BI "\-gdwarf" "level"
+Request debugging information and also use \c
+.I level\c
+\& to specify how
+much information. The default level is 2.
+
+Level 1 produces minimal information, enough for making backtraces in
+parts of the program that you don't plan to debug. This includes
+descriptions of functions and external variables, but no information
+about local variables and no line numbers.
+.TP
+.B \-p
+Generate extra code to write profile information suitable for the
+analysis program \c
+.B prof\c
+\&.
+.TP
+.B \-pg
+Generate extra code to write profile information suitable for the
+analysis program \c
+.B gprof\c
+\&.
+.TP
+.B \-a
+Generate extra code to write profile information for basic blocks,
+which will record the number of times each basic block is executed.
+This data could be analyzed by a program like \c
+.B tcov\c
+\&. Note,
+however, that the format of the data is not what \c
+.B tcov\c
+\& expects.
+Eventually GNU \c
+.B gprof\c
+\& should be extended to process this data.
+.TP
+.BI "\-d" "letters"\c
+\&
+Says to make debugging dumps during compilation at times specified by
+\c
+.I letters\c
+\&. This is used for debugging the compiler. The file names
+for most of the dumps are made by appending a word to the source file
+name (e.g., `\|\c
+.B foo.c.rtl\c
+\&\|' or `\|\c
+.B foo.c.jump\c
+\&\|').
+.TP
+.B \-dM
+Dump all macro definitions, at the end of preprocessing, and write no
+output.
+.TP
+.B \-dN
+Dump all macro names, at the end of preprocessing.
+.TP
+.B \-dD
+Dump all macro definitions, at the end of preprocessing, in addition to
+normal output.
+.TP
+.B \-dy
+Dump debugging information during parsing, to the standard error.
+.TP
+.B \-dr
+Dump after RTL generation, to `\|\c
+.B \c
+.I file\c
+\&.rtl\c
+\&\|'.
+.TP
+.B \-dx
+Just generate RTL for a function instead of compiling it. Usually used
+with `\|\c
+.B r\c
+\&\|'.
+.TP
+.B \-dj
+Dump after first jump optimization, to `\|\c
+.B \c
+.I file\c
+\&.jump\c
+\&\|'.
+.TP
+.B \-ds
+Dump after CSE (including the jump optimization that sometimes
+follows CSE), to `\|\c
+.B \c
+.I file\c
+\&.cse\c
+\&\|'.
+.TP
+.B \-dL
+Dump after loop optimization, to `\|\c
+.B \c
+.I file\c
+\&.loop\c
+\&\|'.
+.TP
+.B \-dt
+Dump after the second CSE pass (including the jump optimization that
+sometimes follows CSE), to `\|\c
+.B \c
+.I file\c
+\&.cse2\c
+\&\|'.
+.TP
+.B \-df
+Dump after flow analysis, to `\|\c
+.B \c
+.I file\c
+\&.flow\c
+\&\|'.
+.TP
+.B \-dc
+Dump after instruction combination, to `\|\c
+.B \c
+.I file\c
+\&.combine\c
+\&\|'.
+.TP
+.B \-dS
+Dump after the first instruction scheduling pass, to
+`\|\c
+.B \c
+.I file\c
+\&.sched\c
+\&\|'.
+.TP
+.B \-dl
+Dump after local register allocation, to `\|\c
+.B \c
+.I file\c
+\&.lreg\c
+\&\|'.
+.TP
+.B \-dg
+Dump after global register allocation, to `\|\c
+.B \c
+.I file\c
+\&.greg\c
+\&\|'.
+.TP
+.B \-dR
+Dump after the second instruction scheduling pass, to
+`\|\c
+.B \c
+.I file\c
+\&.sched2\c
+\&\|'.
+.TP
+.B \-dJ
+Dump after last jump optimization, to `\|\c
+.B \c
+.I file\c
+\&.jump2\c
+\&\|'.
+.TP
+.B \-dd
+Dump after delayed branch scheduling, to `\|\c
+.B \c
+.I file\c
+\&.dbr\c
+\&\|'.
+.TP
+.B \-dk
+Dump after conversion from registers to stack, to `\|\c
+.B \c
+.I file\c
+\&.stack\c
+\&\|'.
+.TP
+.B \-dm
+Print statistics on memory usage, at the end of the run, to
+the standard error.
+.TP
+.B \-dp
+Annotate the assembler output with a comment indicating which
+pattern and alternative was used.
+.TP
+.B \-fpretend\-float
+When running a cross-compiler, pretend that the target machine uses the
+same floating point format as the host machine. This causes incorrect
+output of the actual floating constants, but the actual instruction
+sequence will probably be the same as GNU CC would make when running on
+the target machine.
+.TP
+.B \-save\-temps
+Store the usual ``temporary'' intermediate files permanently; place them
+in the current directory and name them based on the source file. Thus,
+compiling `\|\c
+.B foo.c\c
+\&\|' with `\|\c
+.B \-c \-save\-temps\c
+\&\|' would produce files
+`\|\c
+.B foo.cpp\c
+\&\|' and `\|\c
+.B foo.s\c
+\&\|', as well as `\|\c
+.B foo.o\c
+\&\|'.
+.PP
+
+.SH OPTIMIZATION OPTIONS
+These options control various sorts of optimizations:
+.TP
+.B \-O
+Optimize. Optimizing compilation takes somewhat more time, and a lot
+more memory for a large function.
+
+Without `\|\c
+.B \-O\c
+\&\|', the compiler's goal is to reduce the cost of
+compilation and to make debugging produce the expected results.
+Statements are independent: if you stop the program with a breakpoint
+between statements, you can then assign a new value to any variable or
+change the program counter to any other statement in the function and
+get exactly the results you would expect from the source code.
+
+Without `\|\c
+.B \-O\c
+\&\|', only variables declared \c
+.B register\c
+\& are
+allocated in registers. The resulting compiled code is a little worse
+than produced by PCC without `\|\c
+.B \-O\c
+\&\|'.
+
+With `\|\c
+.B \-O\c
+\&\|', the compiler tries to reduce code size and execution
+time.
+
+When you specify `\|\c
+.B \-O\c
+\&\|', `\|\c
+.B \-fthread\-jumps\c
+\&\|' and
+`\|\c
+.B \-fdelayed\-branch\c
+\&\|' are turned on. On some machines other
+flags may also be turned on.
+.TP
+.B \-O2
+Highly optimize. As compared to `\|\c
+.B \-O\c
+\&\|', this
+option will increase both compilation time and the performance of the
+generated code.
+
+All `\|\c
+.B \-f\c
+.I flag\c
+\&\c
+\&\|' options that control optimization are turned on
+when you specify `\|\c
+.B \-O2\c
+\&\|', except `\|\c
+.B \-funroll\-loops\c
+\&\|'
+and `\|\c
+.B \-funroll\-all\-loops\c
+\&\|'.
+.PP
+
+Options of the form `\|\c
+.B \-f\c
+.I flag\c
+\&\c
+\&\|' specify machine-independent
+flags. Most flags have both positive and negative forms; the negative
+form of `\|\c
+.B \-ffoo\c
+\&\|' would be `\|\c
+.B \-fno\-foo\c
+\&\|'. The following list shows
+only one form\(em\&the one which is not the default.
+You can figure out the other form by either removing `\|\c
+.B no\-\c
+\&\|' or
+adding it.
+.TP
+.B \-ffloat\-store
+Do not store floating point variables in registers. This
+prevents undesirable excess precision on machines such as the
+68000 where the floating registers (of the 68881) keep more
+precision than a \c
+.B double\c
+\& is supposed to have.
+
+For most programs, the excess precision does only good, but a few
+programs rely on the precise definition of IEEE floating point.
+Use `\|\c
+.B \-ffloat\-store\c
+\&\|' for such programs.
+.TP
+.B \-fmemoize\-lookups
+.TP
+.B \-fsave\-memoized
+.I
+(C++ only.)
+These flags are used to get the compiler to compile programs faster
+using heuristics. They are not on by default since they are only effective
+about half the time. The other half of the time programs compile more
+slowly (and take more memory).
+
+The first time the compiler must build a call to a member function (or
+reference to a data member), it must (1) determine whether the class
+implements member functions of that name; (2) resolve which member
+function to call (which involves figuring out what sorts of type
+conversions need to be made); and (3) check the visibility of the member
+function to the caller. All of this adds up to slower compilation.
+Normally, the second time a call is made to that member function (or
+reference to that data member), it must go through the same lengthy
+process again. This means that code like this
+.sp
+.br
+\ \ cout\ <<\ "This\ "\ <<\ p\ <<\ "\ has\ "\ <<\ n\ <<\ "\ legs.\en";
+.br
+.sp
+makes six passes through all three steps. By using a software cache,
+a ``hit'' significantly reduces this cost. Unfortunately, using the
+cache introduces another layer of mechanisms which must be implemented,
+and so incurs its own overhead. `\|\c
+.B \-fmemoize\-lookups\c
+\&\|' enables
+the software cache.
+
+Because access privileges (visibility) to members and member functions
+may differ from one function context to the next,
+.B g++
+may need to flush the cache. With the `\|\c
+.B \-fmemoize\-lookups\c
+\&\|' flag, the cache is flushed after every
+function that is compiled. The `\|\c
+\-fsave\-memoized\c
+\&\|' flag enables the same software cache, but when the compiler
+determines that the context of the last function compiled would yield
+the same access privileges of the next function to compile, it
+preserves the cache.
+This is most helpful when defining many member functions for the same
+class: with the exception of member functions which are friends of
+other classes, each member function has exactly the same access
+privileges as every other, and the cache need not be flushed.
+.TP
+.B \-fno\-default\-inline
+.I
+(C++ only.)
+If `\|\c
+.B \-fdefault\-inline\c
+\&\|' is enabled then member functions defined inside class
+scope are compiled inline by default; i.e., you don't need to
+add `\|\c
+.B inline\c
+\&\|' in front of the member function name. By popular
+demand, this option is now the default. To keep GNU C++ from inlining
+these member functions, specify `\|\c
+.B \-fno\-default\-inline\c
+\&\|'.
+.TP
+.B \-fno\-defer\-pop
+Always pop the arguments to each function call as soon as that
+function returns. For machines which must pop arguments after a
+function call, the compiler normally lets arguments accumulate on the
+stack for several function calls and pops them all at once.
+.TP
+.B \-fforce\-mem
+Force memory operands to be copied into registers before doing
+arithmetic on them. This may produce better code by making all
+memory references potential common subexpressions. When they are
+not common subexpressions, instruction combination should
+eliminate the separate register-load. I am interested in hearing
+about the difference this makes.
+.TP
+.B \-fforce\-addr
+Force memory address constants to be copied into registers before
+doing arithmetic on them. This may produce better code just as
+`\|\c
+.B \-fforce\-mem\c
+\&\|' may. I am interested in hearing about the
+difference this makes.
+.TP
+.B \-fomit\-frame\-pointer
+Don't keep the frame pointer in a register for functions that
+don't need one. This avoids the instructions to save, set up and
+restore frame pointers; it also makes an extra register available
+in many functions. \c
+.I It also makes debugging impossible on
+most machines.\c
+\&
+
+On some machines, such as the Vax, this flag has no effect, because
+the standard calling sequence automatically handles the frame pointer
+and nothing is saved by pretending it doesn't exist. The
+machine-description macro \c
+.B FRAME_POINTER_REQUIRED\c
+\& controls
+whether a target machine supports this flag.
+.TP
+.B \-finline
+Pay attention the \c
+.B inline\c
+\& keyword. Normally the negation of this
+option `\|\c
+.B \-fno\-inline\c
+\&\|' is used to keep the compiler from expanding
+any functions inline. However, the opposite effect may be desirable
+when compiling with `\|\c
+.B \-g\c
+\&\|', since `\|\c
+.B \-g\c
+\&\|' normally turns off all
+inline function expansion.
+.TP
+.B \-finline\-functions
+Integrate all simple functions into their callers. The compiler
+heuristically decides which functions are simple enough to be worth
+integrating in this way.
+
+If all calls to a given function are integrated, and the function is
+declared \c
+.B static\c
+\&, then GCC normally does not output the function as
+assembler code in its own right.
+.TP
+.B \-fcaller\-saves
+Enable values to be allocated in registers that will be clobbered by
+function calls, by emitting extra instructions to save and restore the
+registers around such calls. Such allocation is done only when it
+seems to result in better code than would otherwise be produced.
+
+This option is enabled by default on certain machines, usually those
+which have no call-preserved registers to use instead.
+.TP
+.B \-fkeep\-inline\-functions
+Even if all calls to a given function are integrated, and the function
+is declared \c
+.B static\c
+\&, nevertheless output a separate run-time
+callable version of the function.
+.TP
+.B \-fno\-function\-cse
+Do not put function addresses in registers; make each instruction that
+calls a constant function contain the function's address explicitly.
+
+This option results in less efficient code, but some strange hacks
+that alter the assembler output may be confused by the optimizations
+performed when this option is not used.
+.PP
+
+The following options control specific optimizations. The `\|\c
+.B \-O2\c
+\&\|'
+option turns on all of these optimizations except `\|\c
+.B \-funroll\-loops\c
+\&\|'
+and `\|\c
+.B \-funroll\-all\-loops\c
+\&\|'.
+
+The `\|\c
+.B \-O\c
+\&\|' option usually turns on
+the `\|\c
+.B \-fthread\-jumps\c
+\&\|' and `\|\c
+.B \-fdelayed\-branch\c
+\&\|' options, but
+specific machines may change the default optimizations.
+
+You can use the following flags in the rare cases when ``fine-tuning''
+of optimizations to be performed is desired.
+.TP
+.B \-fstrength\-reduce
+Perform the optimizations of loop strength reduction and
+elimination of iteration variables.
+.TP
+.B \-fthread\-jumps
+Perform optimizations where we check to see if a jump branches to a
+location where another comparison subsumed by the first is found. If
+so, the first branch is redirected to either the destination of the
+second branch or a point immediately following it, depending on whether
+the condition is known to be true or false.
+.TP
+.B \-funroll\-loops
+Perform the optimization of loop unrolling. This is only done for loops
+whose number of iterations can be determined at compile time or run time.
+.TP
+.B \-funroll\-all\-loops
+Perform the optimization of loop unrolling. This is done for all loops.
+This usually makes programs run more slowly.
+.TP
+.B \-fcse\-follow\-jumps
+In common subexpression elimination, scan through jump instructions in
+certain cases. This is not as powerful as completely global CSE, but
+not as slow either.
+.TP
+.B \-frerun\-cse\-after\-loop
+Re-run common subexpression elimination after loop optimizations has been
+performed.
+.TP
+.B \-felide\-constructors
+.I
+(C++ only.)
+Use this option to instruct the compiler to be smarter about when it can
+elide constructors. Without this flag, GNU C++ and cfront both
+generate effectively the same code for:
+.sp
+.br
+A\ foo\ ();
+.br
+A\ x\ (foo\ ());\ \ \ //\ x\ initialized\ by\ `foo\ ()',\ no\ ctor\ called
+.br
+A\ y\ =\ foo\ ();\ \ \ //\ call\ to\ `foo\ ()'\ heads\ to\ temporary,
+.br
+\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ //\ y\ is\ initialized\ from\ the\ temporary.
+.br
+.sp
+Note the difference! With this flag, GNU C++ initializes `\|\c
+.B y\c
+\&\|' directly
+from the call to
+.B foo ()
+without going through a temporary.
+.TP
+.B \-fexpensive\-optimizations
+Perform a number of minor optimizations that are relatively expensive.
+.TP
+.B \-fdelayed\-branch
+If supported for the target machine, attempt to reorder instructions
+to exploit instruction slots available after delayed branch
+instructions.
+.TP
+.B \-fschedule\-insns
+If supported for the target machine, attempt to reorder instructions to
+eliminate execution stalls due to required data being unavailable. This
+helps machines that have slow floating point or memory load instructions
+by allowing other instructions to be issued until the result of the load
+or floating point instruction is required.
+.TP
+.B \-fschedule\-insns2
+Similar to `\|\c
+.B \-fschedule\-insns\c
+\&\|', but requests an additional pass of
+instruction scheduling after register allocation has been done. This is
+especially useful on machines with a relatively small number of
+registers and where memory load instructions take more than one cycle.
+.PP
+
+.SH TARGET OPTIONS
+By default, GNU CC compiles code for the same type of machine that you
+are using. However, it can also be installed as a cross-compiler, to
+compile for some other type of machine. In fact, several different
+configurations of GNU CC, for different target machines, can be
+installed side by side. Then you specify which one to use with the
+`\|\c
+.B \-b\c
+\&\|' option.
+
+In addition, older and newer versions of GNU CC can be installed side
+by side. One of them (probably the newest) will be the default, but
+you may sometimes wish to use another.
+.TP
+.BI "\-b " "machine"\c
+\&
+The argument \c
+.I machine\c
+\& specifies the target machine for compilation.
+This is useful when you have installed GNU CC as a cross-compiler.
+
+The value to use for \c
+.I machine\c
+\& is the same as was specified as the
+machine type when configuring GNU CC as a cross-compiler. For
+example, if a cross-compiler was configured with `\|\c
+.B configure
+i386v\c
+\&\|', meaning to compile for an 80386 running System V, then you
+would specify `\|\c
+.B \-b i386v\c
+\&\|' to run that cross compiler.
+
+When you do not specify `\|\c
+.B \-b\c
+\&\|', it normally means to compile for
+the same type of machine that you are using.
+.TP
+.BI "\-V " "version"\c
+\&
+The argument \c
+.I version\c
+\& specifies which version of GNU CC to run.
+This is useful when multiple versions are installed. For example,
+\c
+.I version\c
+\& might be `\|\c
+.B 2.0\c
+\&\|', meaning to run GNU CC version 2.0.
+
+The default version, when you do not specify `\|\c
+.B \-V\c
+\&\|', is controlled
+by the way GNU CC is installed. Normally, it will be a version that
+is recommended for general use.
+.PP
+
+.SH MACHINE DEPENDENT OPTIONS
+Each of the target machine types can have its own special options,
+starting with `\|\c
+.B \-m\c
+\&\|', to choose among various hardware models or
+configurations\(em\&for example, 68010 vs 68020, floating coprocessor or
+none. A single installed version of the compiler can compile for any
+model or configuration, according to the options specified.
+
+These are the `\|\c
+.B \-m\c
+\&\|' options defined for the 68000 series:
+.TP
+.B \-m68020
+.TP
+.B \-mc68020
+Generate output for a 68020 (rather than a 68000). This is the
+default if you use the unmodified sources.
+.TP
+.B \-m68000
+.TP
+.B \-mc68000
+Generate output for a 68000 (rather than a 68020).
+.TP
+.B \-m68881
+Generate output containing 68881 instructions for floating point.
+This is the default if you use the unmodified sources.
+.TP
+.B \-mfpa
+Generate output containing Sun FPA instructions for floating point.
+.TP
+.B \-msoft\-float
+Generate output containing library calls for floating point.
+.I
+WARNING:
+the requisite libraries are not part of GNU CC. Normally the
+facilities of the machine's usual C compiler are used, but this can't
+be done directly in cross-compilation. You must make your own
+arrangements to provide suitable library functions for cross-compilation.
+.TP
+.B \-mshort
+Consider type \c
+.B int\c
+\& to be 16 bits wide, like \c
+.B short int\c
+\&.
+.TP
+.B \-mnobitfield
+Do not use the bit-field instructions. `\|\c
+.B \-m68000\c
+\&\|' implies
+`\|\c
+.B \-mnobitfield\c
+\&\|'.
+.TP
+.B \-mbitfield
+Do use the bit-field instructions. `\|\c
+.B \-m68020\c
+\&\|' implies
+`\|\c
+.B \-mbitfield\c
+\&\|'. This is the default if you use the unmodified
+sources.
+.TP
+.B \-mrtd
+Use a different function-calling convention, in which functions
+that take a fixed number of arguments return with the \c
+.B rtd\c
+\&
+instruction, which pops their arguments while returning. This
+saves one instruction in the caller since there is no need to pop
+the arguments there.
+
+This calling convention is incompatible with the one normally
+used on Unix, so you cannot use it if you need to call libraries
+compiled with the Unix compiler.
+
+Also, you must provide function prototypes for all functions that
+take variable numbers of arguments (including \c
+.B printf\c
+\&);
+otherwise incorrect code will be generated for calls to those
+functions.
+
+In addition, seriously incorrect code will result if you call a
+function with too many arguments. (Normally, extra arguments are
+harmlessly ignored.)
+
+The \c
+.B rtd\c
+\& instruction is supported by the 68010 and 68020
+processors, but not by the 68000.
+.PP
+
+These `\|\c
+.B \-m\c
+\&\|' options are defined for the Vax:
+.TP
+.B \-munix
+Do not output certain jump instructions (\c
+.B aobleq\c
+\& and so on)
+that the Unix assembler for the Vax cannot handle across long
+ranges.
+.TP
+.B \-mgnu
+Do output those jump instructions, on the assumption that you
+will assemble with the GNU assembler.
+.TP
+.B \-mg
+Output code for g-format floating point numbers instead of d-format.
+.PP
+
+These `\|\c
+.B \-m\c
+\&\|' switches are supported on the Sparc:
+.TP
+.B \-mfpu
+Generate output containing floating point instructions. This is the
+default if you use the unmodified sources.
+.TP
+.B \-mno\-epilogue
+Generate separate return instructions for \c
+.B return\c
+\& statements.
+This has both advantages and disadvantages; I don't recall what they
+are.
+.PP
+
+These `\|\c
+.B \-m\c
+\&\|' options are defined for the Convex:
+.TP
+.B \-mc1
+Generate output for a C1. This is the default when the compiler is
+configured for a C1.
+.TP
+.B \-mc2
+Generate output for a C2. This is the default when the compiler is
+configured for a C2.
+.TP
+.B \-margcount
+Generate code which puts an argument count in the word preceding each
+argument list. Some non-portable Convex and Vax programs need this word.
+(Debuggers don't, except for functions with variable-length argument
+lists; this information is in the symbol table.)
+.TP
+.B \-mnoargcount
+Omit the argument count word. This is the default if you use the
+unmodified sources.
+.PP
+
+These `\|\c
+.B \-m\c
+\&\|' options are defined for the AMD Am29000:
+.TP
+.B \-mdw
+Generate code that assumes the DW bit is set, i.e., that byte and
+halfword operations are directly supported by the hardware. This is the
+default.
+.TP
+.B \-mnodw
+Generate code that assumes the DW bit is not set.
+.TP
+.B \-mbw
+Generate code that assumes the system supports byte and halfword write
+operations. This is the default.
+.TP
+.B \-mnbw
+Generate code that assumes the systems does not support byte and
+halfword write operations. This implies `\|\c
+.B \-mnodw\c
+\&\|'.
+.TP
+.B \-msmall
+Use a small memory model that assumes that all function addresses are
+either within a single 256 KB segment or at an absolute address of less
+than 256K. This allows the \c
+.B call\c
+\& instruction to be used instead
+of a \c
+.B const\c
+\&, \c
+.B consth\c
+\&, \c
+.B calli\c
+\& sequence.
+.TP
+.B \-mlarge
+Do not assume that the \c
+.B call\c
+\& instruction can be used; this is the
+default.
+.TP
+.B \-m29050
+Generate code for the Am29050.
+.TP
+.B \-m29000
+Generate code for the Am29000. This is the default.
+.TP
+.B \-mkernel\-registers
+Generate references to registers \c
+.B gr64-gr95\c
+\& instead of
+\c
+.B gr96-gr127\c
+\&. This option can be used when compiling kernel code
+that wants a set of global registers disjoint from that used by
+user-mode code.
+
+Note that when this option is used, register names in `\|\c
+.B \-f\c
+\&\|' flags
+must use the normal, user-mode, names.
+.TP
+.B \-muser\-registers
+Use the normal set of global registers, \c
+.B gr96-gr127\c
+\&. This is the
+default.
+.TP
+.B \-mstack\-check
+Insert a call to \c
+.B __msp_check\c
+\& after each stack adjustment. This
+is often used for kernel code.
+.PP
+
+These `\|\c
+.B \-m\c
+\&\|' options are defined for Motorola 88K architectures:
+.TP
+.B \-mbig\-pic
+Emit position-independent code, suitable for dynamic linking, even if
+branches need large displacements. Equivalent to the general-use option `\|\c
+.B \-fPIC\c
+\&\|'.
+The general-use option `\|\c
+.B \-fpic\c
+\&\|',
+by contrast, only emits valid 88k code if all branches involve small
+displacements.
+GCC does not emit position-independent code by default.
+.TP
+.B \-midentify\-revision
+Include an \c
+.B ident\c
+\& directive in the assembler output recording the
+source file name, compiler name and version, timestamp, and compilation
+flags used.
+.TP
+.B \-mno\-underscores
+In assembler output, emit symbol names without adding an underscore
+character at the beginning of each name. The default is to use an
+underscore as prefix on each name.
+.TP
+.B \-mno\-check\-zero\-division
+.TP
+.B \-mcheck\-zero\-division
+Early models of the 88K architecture had problems with division by zero;
+in particular, many of them didn't trap. Use these options to avoid
+including (or to include explicitly) additional code to detect division
+by zero and signal an exception. All GCC configurations for the 88K use
+`\|\c
+.B \-mcheck\-zero\-division\c
+\&\|' by default.
+.TP
+.B \-mocs\-debug\-info
+.TP
+.B \-mno\-ocs\-debug\-info
+Include (or omit) additional debugging information (about
+registers used in each stack frame) as specified in the 88Open Object
+Compatibility Standard, ``OCS''. This extra information is not needed
+by GDB. The default for DG/UX, SVr4, and Delta 88 SVr3.2 is to
+include this information; other 88k configurations omit this information
+by default.
+.TP
+.B \-mocs\-frame\-position
+.TP
+.B \-mno\-ocs\-frame\-position
+Force (or do not require) register values to be stored in a particular
+place in stack frames, as specified in OCS. The DG/UX, Delta88 SVr3.2,
+and BCS configurations use `\|\c
+.B \-mocs\-frame\-position\c
+\&\|'; other 88k
+configurations have the default `\|\c
+.B \-mno\-ocs\-frame\-position\c
+\&\|'.
+.TP
+.B \-moptimize\-arg\-area
+.TP
+.B \-mno\-optimize\-arg\-area
+Control how to store function arguments in stack frames.
+`\|\c
+.B \-moptimize\-arg\-area\c
+\&\|' saves space, but may break some
+debuggers (not GDB). `\|\c
+.B \-mno\-optimize\-arg\-area\c
+\&\|' conforms better to
+standards. By default GCC does not optimize the argument area.
+.TP
+.BI "\-mshort\-data\-" "num"\c
+\&
+.I num\c
+\&
+Generate smaller data references by making them relative to \c
+.B r0\c
+\&,
+which allows loading a value using a single instruction (rather than the
+usual two). You control which data references are affected by
+specifying \c
+.I num\c
+\& with this option. For example, if you specify
+`\|\c
+.B \-mshort\-data\-512\c
+\&\|', then the data references affected are those
+involving displacements of less than 512 bytes.
+`\|\c
+.B \-mshort\-data\-\c
+.I num\c
+\&\c
+\&\|' is not effective for \c
+.I num\c
+\& greater
+than 64K.
+.TP
+.B \-msvr4
+.TP
+.B \-msvr3
+Turn on (`\|\c
+.B \-msvr4\c
+\&\|') or off (`\|\c
+.B \-msvr3\c
+\&\|') compiler extensions
+related to System V release 4 (SVr4). This controls the following:
+.TP
+\ \ \ \(bu
+Which variant of the assembler syntax to emit (which you can select
+independently using `\|\c
+.B \-mversion03.00\c
+\&\|').
+.TP
+\ \ \ \(bu
+`\|\c
+.B \-msvr4\c
+\&\|' makes the C preprocessor recognize `\|\c
+.B #pragma weak\c
+\&\|'
+.TP
+\ \ \ \(bu
+`\|\c
+.B \-msvr4\c
+\&\|' makes GCC issue additional declaration directives used in
+SVr4.
+.PP
+`\|\c
+.B \-msvr3\c
+\&\|' is the default for all m88K configurations except
+the SVr4 configuration.
+.TP
+.B \-mtrap\-large\-shift
+.TP
+.B \-mhandle\-large\-shift
+Include code to detect bit-shifts of more than 31 bits; respectively,
+trap such shifts or emit code to handle them properly. By default GCC
+makes no special provision for large bit shifts.
+.TP
+.B \-muse\-div\-instruction
+Very early models of the 88K architecture didn't have a divide
+instruction, so GCC avoids that instruction by default. Use this option
+to specify that it's safe to use the divide instruction.
+.TP
+.B \-mversion\-03.00
+Use alternative assembler syntax for the assembler version corresponding
+to SVr4, but without enabling the other features triggered by
+`\|\c
+.B \-svr4\c
+\&\|'. This is implied by `\|\c
+.B \-svr4\c
+\&\|', is the default for the
+SVr4 configuration of GCC, and is permitted by the DG/UX configuration
+only if `\|\c
+.B \-svr4\c
+\&\|' is also specified. The Delta 88 SVr3.2
+configuration ignores this option.
+.TP
+.B \-mwarn\-passed\-structs
+Warn when a function passes a struct as an argument or result.
+Structure-passing conventions have changed during the evolution of the C
+language, and are often the source of portability problems. By default,
+GCC issues no such warning.
+.PP
+These options are defined for the IBM RS6000:
+
+.PP
+.B \-mfp\-in\-toc
+.TP
+.B \-mno\-fp\-in\-toc
+Control whether or not floating-point constants go in the Table of
+Contents (TOC), a table of all global variable and function addresses. By
+default GCC puts floating-point constants there; if the TOC overflows,
+`\|\c
+.B \-mno\-fp\-in\-toc\c
+\&\|' will reduce the size of the TOC, which may avoid
+the overflow.
+
+.PP
+These `\|\c
+.B \-m\c
+\&\|' options are defined for the IBM RT PC:
+.TP
+.B \-min\-line\-mul
+Use an in-line code sequence for integer multiplies. This is the
+default.
+.TP
+.B \-mcall\-lib\-mul
+Call \c
+.B lmul$$\c
+\& for integer multiples.
+.TP
+.B \-mfull\-fp\-blocks
+Generate full-size floating point data blocks, including the minimum
+amount of scratch space recommended by IBM. This is the default.
+.TP
+.B \-mminimum\-fp\-blocks
+Do not include extra scratch space in floating point data blocks. This
+results in smaller code, but slower execution, since scratch space must
+be allocated dynamically.
+.TP
+.B \-mfp\-arg\-in\-fpregs
+Use a calling sequence incompatible with the IBM calling convention in
+which floating point arguments are passed in floating point registers.
+Note that \c
+.B varargs.h\c
+\& and \c
+.B stdargs.h\c
+\& will not work with
+floating point operands if this option is specified.
+.TP
+.B \-mfp\-arg\-in\-gregs
+Use the normal calling convention for floating point arguments. This is
+the default.
+.TP
+.B \-mhc\-struct\-return
+Return structures of more than one word in memory, rather than in a
+register. This provides compatibility with the MetaWare HighC (hc)
+compiler. Use `\|\c
+.B \-fpcc\-struct\-return\c
+\&\|' for compatibility with the
+Portable C Compiler (pcc).
+.TP
+.B \-mnohc\-struct\-return
+Return some structures of more than one word in registers, when
+convenient. This is the default. For compatibility with the
+IBM-supplied compilers, use either `\|\c
+.B \-fpcc\-struct\-return\c
+\&\|' or
+`\|\c
+.B \-mhc\-struct\-return\c
+\&\|'.
+.PP
+These `\|\c
+.B \-m\c
+\&\|' options are defined for the MIPS family of computers:
+.TP
+.BI "\-mcpu=" "cpu-type"
+Assume the defaults for the machine type
+.I cpu-type
+when
+scheduling instructions. The default
+.I cpu-type
+is
+.BR default ,
+which picks the longest cycles times for any of the machines, in order
+that the code run at reasonable rates on all MIPS cpu's. Other
+choices for
+.I cpu-type
+are
+.BR r2000 ,
+.BR r3000 ,
+.BR r4000 ,
+and
+.BR r6000 .
+While picking a specific
+.I cpu-type
+will schedule things appropriately for that particular chip, the
+compiler will not generate any code that does not meet level 1 of the
+MIPS ISA (instruction set architecture) without the
+.B \-mips2
+or
+.B \-mips3
+switches being used.
+.TP
+.B \-mips2
+Issue instructions from level 2 of the MIPS ISA (branch likely, square
+root instructions). The
+.B \-mcpu=r4000
+or
+.B \-mcpu=r6000
+switch must be used in conjunction with
+.BR \-mips2 .
+.TP
+.B \-mips3
+Issue instructions from level 3 of the MIPS ISA (64 bit instructions).
+The
+.B \-mcpu=r4000
+switch must be used in conjunction with
+.BR \-mips2 .
+.TP
+.B \-mint64
+.TP
+.B \-mlong64
+.TP
+.B \-mlonglong128
+These options don't work at present.
+.TP
+.B \-mmips\-as
+Generate code for the MIPS assembler, and invoke
+.B mips\-tfile
+to add normal debug information. This is the default for all
+platforms except for the OSF/1 reference platform, using the OSF/rose
+object format. If any of the
+.BR \-ggdb ,
+.BR \-gstabs ,
+or
+.B \-gstabs+
+switches are used, the
+.B mips\-tfile
+program will encapsulate the stabs within MIPS ECOFF.
+.TP
+.B \-mgas
+Generate code for the GNU assembler. This is the default on the OSF/1
+reference platform, using the OSF/rose object format.
+.TP
+.B \-mrnames
+.TP
+.B \-mno\-rnames
+The
+.B \-mrnames
+switch says to output code using the MIPS software names for the
+registers, instead of the hardware names (ie,
+.B a0
+instead of
+.BR $4 ).
+The GNU assembler does not support the
+.B \-mrnames
+switch, and the MIPS assembler will be instructed to run the MIPS C
+preprocessor over the source file. The
+.B \-mno\-rnames
+switch is default.
+.TP
+.B \-mgpopt
+.TP
+.B \-mno\-gpopt
+The
+.B \-mgpopt
+switch says to write all of the data declarations before the
+instructions in the text section, to all the MIPS assembler to
+generate one word memory references instead of using two words for
+short global or static data items. This is on by default if
+optimization is selected.
+.TP
+.B \-mstats
+.TP
+.B \-mno\-stats
+For each non-inline function processed, the
+.B \-mstats
+switch causes the compiler to emit one line to the standard error file
+to print statistics about the program (number of registers saved,
+stack size, etc.).
+.TP
+.B \-mmemcpy
+.TP
+.B \-mno\-memcpy
+The
+.B \-mmemcpy
+switch makes all block moves call the appropriate string function
+.RB ( memcpy
+or
+.BR bcopy )
+instead of possibly generating inline code.
+.TP
+.B \-mmips\-tfile
+.TP
+.B \-mno\-mips\-tfile
+The
+.B \-mno\-mips\-tfile
+switch causes the compiler not postprocess the object file with the
+.B mips\-tfile
+program, after the MIPS assembler has generated it to add debug
+support. If
+.B mips\-tfile
+is not run, then no local variables will be available to the debugger.
+In addition,
+.B stage2
+and
+.B stage3
+objects will have the temporary file names passed to the assembler
+embedded in the object file, which means the objects will not compare
+the same.
+.TP
+.B \-msoft\-float
+Generate output containing library calls for floating point.
+.I
+WARNING:
+the requisite libraries are not part of GNU CC. Normally the
+facilities of the machine's usual C compiler are used, but this can't
+be done directly in cross-compilation. You must make your own
+arrangements to provide suitable library functions for cross-compilation.
+.TP
+.B \-mhard\-float
+Generate output containing floating point instructions. This is the
+default if you use the unmodified sources.
+.TP
+.B \-mfp64
+Assume that the
+.B FR
+bit in the status word is on, and that there are 32 64-bit floating
+point registers, instead of 32 32-bit floating point registers. You
+must also specify the
+.B \-mcpu=r4000
+and
+.B \-mips3
+switches.
+.TP
+.B \-mfp32
+Assume that there are 32 32-bit floating point registers. This is the
+default.
+.TP
+.B \-mabicalls
+The
+.B \-mabicalls
+switch says to emit the
+.BR \&.abicalls ,
+.BR \&.cpload ,
+and
+.B \&.cprestore
+pseudo operations that some System V.4 ports use for position
+independent code.
+.TP
+.B \-mhalf\-pic
+.TP
+.B \-mno\-half\-pic
+The
+.B \-mhalf\-pic
+switch says to put pointers to extern references into the data section
+and load them up, rather than put the references in the text section.
+This option does not work at present.
+.B
+.BI \-G num
+Put global and static items less than or equal to
+.I num
+bytes into the small data or bss sections instead of the normal data
+or bss section. This allows the assembler to emit one word memory
+reference instructions based on the global pointer
+.RB ( gp
+or
+.BR $28 ),
+instead of the normal two words used. By default,
+.I num
+is 8 when the MIPS assembler is used, and 0 when the GNU
+assembler is used. The
+.BI \-G num
+switch is also passed to the assembler and linker. All modules should
+be compiled with the same
+.BI \-G num
+value.
+.PP
+
+.SH CODE GENERATION OPTIONS
+These machine-independent options control the interface conventions
+used in code generation.
+
+Most of them begin with `\|\c
+\-f\c
+\&\|'. These options have both positive and negative forms; the negative form
+of `\|\c
+.B \-ffoo\c
+\&\|' would be `\|\c
+.B \-fno\-foo\c
+\&\|'. In the table below, only
+one of the forms is listed\(em\&the one which is not the default. You
+can figure out the other form by either removing `\|\c
+.B no\-\c
+\&\|' or adding
+it.
+.TP
+.BI +e N
+.I (C++ only.)
+control whether virtual function definitions in classes
+are used to generate code, or only to define interfaces for their
+callers. These options are provided for compatibility with cfront
+1.x usage; the recommended GNU C++ usage is to use
+.B #pragma interface
+and
+.B
+#pragma implementation\c
+\&, instead.
+
+With `\|\c
+.B +e0\c
+\&\|', virtual function definitions in classes are declared extern;
+the declaration is used only as an interface specification, not to
+generate code for the virtual functions (in this compilation).
+
+With `\|\c
+.B +e1\c
+\&\|',
+.B g++
+actually generates the code implementing virtual functions
+defined in the code, and makes them publicly visible.
+.TP
+.B \-fnonnull\-objects
+.I
+(C++ only.)
+Normally, GNU C++ makes conservative assumptions about objects reached
+through references. For example, the compiler must check that `\|\c
+.B a\c
+\&\|' is not null in code like the following:
+.br
+\ \ \ \ obj\ &a\ =\ g\ ();
+.br
+\ \ \ \ a.f\ (2);
+.br
+Checking that references of this sort have non-null values requires
+extra code, however, and it is unnecessary for many programs. You can
+use `\|\c
+.B \-fnonnull\-objects\c
+\&\|' to omit the checks for null, if your program doesn't require the
+default checking.
+.TP
+.B \-fpcc\-struct\-return
+Use the same convention for returning \c
+.B struct\c
+\& and \c
+.B union\c
+\&
+values that is used by the usual C compiler on your system. This
+convention is less efficient for small structures, and on many
+machines it fails to be reentrant; but it has the advantage of
+allowing intercallability between GCC-compiled code and PCC-compiled
+code.
+.TP
+.B \-fshort\-enums
+Allocate to an \c
+.B enum\c
+\& type only as many bytes as it needs for the
+declared range of possible values. Specifically, the \c
+.B enum\c
+\& type
+will be equivalent to the smallest integer type which has enough room.
+.TP
+.B \-fshort\-double
+Use the same size for
+.B double
+as for
+.B float
+\&.
+.TP
+.B \-fshared\-data
+Requests that the data and non-\c
+.B const\c
+\& variables of this
+compilation be shared data rather than private data. The distinction
+makes sense only on certain operating systems, where shared data is
+shared between processes running the same program, while private data
+exists in one copy per process.
+.TP
+.B \-fno\-common
+Allocate even uninitialized global variables in the bss section of the
+object file, rather than generating them as common blocks. This has the
+effect that if the same variable is declared (without \c
+.B extern\c
+\&) in
+two different compilations, you will get an error when you link them.
+The only reason this might be useful is if you wish to verify that the
+program will work on other systems which always work this way.
+.TP
+.B \-fvolatile
+Consider all memory references through pointers to be volatile.
+.TP
+.B \-fpic
+If supported for the target machines, generate position-independent code,
+suitable for use in a shared library.
+.TP
+.B \-fPIC
+If supported for the target machine, emit position-independent code,
+suitable for dynamic linking, even if branches need large displacements.
+.TP
+.BI "\-ffixed\-" "reg"\c
+\&
+Treat the register named \c
+.I reg\c
+\& as a fixed register; generated code
+should never refer to it (except perhaps as a stack pointer, frame
+pointer or in some other fixed role).
+
+\c
+.I reg\c
+\& must be the name of a register. The register names accepted
+are machine-specific and are defined in the \c
+.B REGISTER_NAMES\c
+\&
+macro in the machine description macro file.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+.TP
+.BI "\-fcall\-used\-" "reg"\c
+\&
+Treat the register named \c
+.I reg\c
+\& as an allocatable register that is
+clobbered by function calls. It may be allocated for temporaries or
+variables that do not live across a call. Functions compiled this way
+will not save and restore the register \c
+.I reg\c
+\&.
+
+Use of this flag for a register that has a fixed pervasive role in the
+machine's execution model, such as the stack pointer or frame pointer,
+will produce disastrous results.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+.TP
+.BI "\-fcall\-saved\-" "reg"\c
+\&
+Treat the register named \c
+.I reg\c
+\& as an allocatable register saved by
+functions. It may be allocated even for temporaries or variables that
+live across a call. Functions compiled this way will save and restore
+the register \c
+.I reg\c
+\& if they use it.
+
+Use of this flag for a register that has a fixed pervasive role in the
+machine's execution model, such as the stack pointer or frame pointer,
+will produce disastrous results.
+
+A different sort of disaster will result from the use of this flag for
+a register in which function values may be returned.
+
+This flag does not have a negative form, because it specifies a
+three-way choice.
+.TP
+.B \-fgnu\-binutils
+.TP
+.B \-fno\-gnu\-binutils
+.I
+(C++ only.)
+`\|\c
+.B \-fgnu\-binutils
+\&\|' (the default for most, but not all, platforms) makes GNU C++
+emit extra information for static initialization and finalization.
+This information has to be passed from the assembler to the GNU
+linker. Some assemblers won't pass this information; you must either
+use GNU
+.B as
+or specify the option `\|\c
+.B \-fno\-gnu\-binutils\c
+\&\|'.
+
+With `\|\c
+.B \-fno\-gnu\-binutils\c
+\&\|', you must use the program
+.B collect
+(part of the GCC distribution) for linking.
+.PP
+
+.SH PRAGMAS
+Two `\|\c
+.B #pragma\c
+\&\|' directives are supported for GNU C++, to permit using the same
+header file for two purposes: as a definition of interfaces to a given
+object class, and as the full definition of the contents of that object class.
+.TP
+.B #pragma interface
+.I (C++ only.)
+Use this directive in header files that define object classes, to save
+space in most of the object files that use those classes. Normally,
+local copies of certain information (backup copies of inline member
+functions, debugging information, and the internal tables that
+implement virtual functions) must be kept in each object file that
+includes class definitions. You can use this pragma to avoid such
+duplication. When a header file containing `\|\c
+.B #pragma interface\c
+\&\|' is included in a compilation, this auxiliary information
+will not be generated (unless the main input source file itself uses
+`\|\c
+.B #pragma implementation\c
+\&\|'). Instead, the object files will contain references to be
+resolved at link time.
+.tr !"
+.TP
+.B #pragma implementation
+.TP
+.BI "#pragma implementation !" objects .h!
+.I (C++ only.)
+Use this pragma in a main input file, when you want full output from
+included header files to be generated (and made globally visible).
+The included header file, in turn, should use `\|\c
+.B #pragma interface\c
+\&\|'.
+Backup copies of inline member functions, debugging information, and
+the internal tables used to implement virtual functions are all
+generated in implementation files.
+
+If you use `\|\c
+.B #pragma implementation\c
+\&\|' with no argument, it applies to an include file with the same
+basename as your source file; for example, in `\|\c
+.B allclass.cc\c
+\&\|', `\|\c
+.B #pragma implementation\c
+\&\|' by itself is equivalent to `\|\c
+.B
+#pragma implementation "allclass.h"\c
+\&\|'. Use the string argument if you want a single implementation
+file to include code from multiple header files.
+
+There is no way to split up the contents of a single header file into
+multiple implementation files.
+.SH FILES
+.ta \w'LIBDIR/g++\-include 'u
+file.c C source file
+.br
+file.h C header (preprocessor) file
+.br
+file.i preprocessed C source file
+.br
+file.C C++ source file
+.br
+file.cc C++ source file
+.br
+file.cxx C++ source file
+.br
+file.m Objective-C source file
+.br
+file.s assembly language file
+.br
+file.o object file
+.br
+a.out link edited output
+.br
+\fITMPDIR\fR/cc\(** temporary files
+.br
+\fILIBDIR\fR/cpp preprocessor
+.br
+\fILIBDIR\fR/cc1 compiler for C
+.br
+\fILIBDIR\fR/cc1plus compiler for C++
+.br
+\fILIBDIR\fR/collect linker front end needed on some machines
+.br
+\fILIBDIR\fR/libgcc.a GCC subroutine library
+.br
+/lib/crt[01n].o start-up routine
+.br
+\fILIBDIR\fR/ccrt0 additional start-up routine for C++
+.br
+/lib/libc.a standard C library, see
+.IR intro (3)
+.br
+/usr/include standard directory for
+.B #include
+files
+.br
+\fILIBDIR\fR/include standard gcc directory for
+.B #include
+files
+.br
+\fILIBDIR\fR/g++\-include additional g++ directory for
+.B #include
+.sp
+.I LIBDIR
+is usually
+.B /usr/local/lib/\c
+.IR machine / version .
+.br
+.I TMPDIR
+comes from the environment variable
+.B TMPDIR
+(default
+.B /usr/tmp
+if available, else
+.B /tmp\c
+\&).
+.SH "SEE ALSO"
+cpp(1), as(1), ld(1), gdb(1), adb(1), dbx(1), sdb(1).
+.br
+.RB "`\|" gcc "\|', `\|" cpp \|',
+.RB `\| as \|', `\| ld \|',
+and
+.RB `\| gdb \|'
+entries in
+.B info\c
+\&.
+.br
+.I
+Using and Porting GNU CC (for version 2.0)\c
+, Richard M. Stallman, November 1990;
+.I
+The C Preprocessor\c
+, Richard M. Stallman, July 1990;
+.I
+Using GDB: A Guide to the GNU Source-Level Debugger\c
+, Richard M. Stallman and Roland H. Pesch, December 1991;
+.I
+Using as: the GNU Assembler\c
+, Dean Elsner, Jay Fenlason & friends, March 1991;
+.I
+gld: the GNU linker\c
+, Steve Chamberlain and Roland Pesch, April 1991.
+
+.SH BUGS
+Report bugs to
+.BR bug\-gcc@prep.ai.mit.edu .
+Bugs tend actually to be fixed if they can be isolated, so it is in your
+interest to report them in such a way that they can be easily reproduced.
+.SH COPYING
+Copyright (c) 1991 Free Software Foundation, Inc.
+.PP
+Permission is granted to make and distribute verbatim copies of
+this manual provided the copyright notice and this permission notice
+are preserved on all copies.
+.PP
+Permission is granted to copy and distribute modified versions of this
+manual under the conditions for verbatim copying, provided that the
+entire resulting derived work is distributed under the terms of a
+permission notice identical to this one.
+.PP
+Permission is granted to copy and distribute translations of this
+manual into another language, under the above conditions for modified
+versions, except that this permission notice may be included in
+translations approved by the Free Software Foundation instead of in
+the original English.
+.SH AUTHORS
+See the GNU CC Manual for the contributors to GNU CC.
projects / unix-history / commitdiff