[unix-history] / usr / man / man1 / m4.1

.TH M4 1 
.SH NAME
m4 \- macro processor
.SH SYNOPSIS
.B m4
[ files ]
.SH DESCRIPTION
.I M4
is a macro processor
intended as a front end for Ratfor, C, and other languages.
Each of the argument files is processed in order;
if there are no arguments, or if an argument is `\-',
the standard input is read.
The processed text is written on the standard output.
.PP
Macro calls
have the form
.PP
	name(arg1,arg2, . . . , argn)
.br
.PP
The `(' must immediately follow the name of the macro.
If a defined macro name is not followed by a `(',
it is deemed to have no arguments.
Leading unquoted blanks, tabs, and newlines are ignored while collecting arguments.
Potential macro names consist of alphabetic letters,
digits, and underscore `\_', where the first character is not a digit.
.PP
Left and right single quotes (\`\|\') are used to quote strings.
The value of a quoted string is the string stripped of the quotes.
.PP
When a macro name is recognized,
its arguments are collected by searching for a matching right
parenthesis.
Macro evaluation proceeds normally during the collection of the arguments,
and any commas or right parentheses
which happen to turn up within the value of a nested
call are as effective as those in the original input text.
After argument collection,
the value of the macro is pushed back onto the input stream
and rescanned.
.PP
.I M4
makes available the following built-in macros.
They may be redefined, but once this is done the original meaning is lost.
Their values are null unless otherwise stated.
.TP 10
define
The second argument is installed as the value of the macro
whose name is the first argument.
Each occurrence of $\fIn\fR in the replacement text,
where
.I n
is a digit,
is replaced by the
.IR n -th
argument.
Argument 0 is the name of the macro;
missing arguments are replaced by the null string.
.TP
undefine
removes the definition of the macro named in its argument.
.TP
ifdef
If the first argument is defined, the value is the second argument, otherwise the third.
If there is no third argument, the value is null.
The word
.I unix
is predefined on UNIX versions of
.IR m4 .
.TP
changequote
Change quote characters to the first and second arguments.
.I Changequote
without arguments restores the original values
(i.e., \`\|\').
.TP
divert
.I M4
maintains 10 output streams,
numbered 0-9.
The final output is the concatenation of the streams
in numerical order;
initially stream 0 is the current stream.
The
.I divert
macro changes the current output stream to its (digit-string)
argument.
Output diverted to a stream other than 0 through 9
is discarded.
.TP
undivert
causes immediate output of text from diversions named as
arguments, or all diversions if no argument.
Text may be undiverted into another diversion.
Undiverting discards the diverted text.
.TP
divnum
returns the value of the current output stream.
.TP
dnl
reads and discards characters up to and including the next newline.
.TP
ifelse
has three or more arguments.
If the first argument is the same string as the second,
then the value is the third argument.
If not, and if there are more than four arguments, the process is repeated with arguments 4, 5, 6 and 7.
Otherwise, the value is either the fourth string, or, if it is not present,
null.
.TP
incr
returns the value of its argument incremented by 1.
The value of the argument is calculated
by interpreting an initial digit-string as a decimal number.
.TP
eval
evaluates its argument as an arithmetic expression, using 32-bit arithmetic.
Operators include +, \-, \(**, /, %, ^ (exponentiation); relationals; parentheses.
.TP
len
returns the number of characters in its argument.
.TP
index
returns the position in its first argument where the second argument begins (zero origin),
or \-1 if the second argument does not occur.
.TP
substr
returns a substring of its first argument.
The second argument is a zero origin
number selecting the first character;
the third argument indicates the length of the substring.
A missing third argument is taken to be large enough to extend to
the end of the first string.
.TP
translit
transliterates the characters in its first argument
from the set given by the second argument to the set given by the third.
No abbreviations are permitted.
.TP
include
returns the contents of the file named in the argument.
.TP
sinclude
is identical to
.I include,
except that it
says nothing if the file is inaccessible.
.TP
syscmd
executes the UNIX command given in the first argument.
No value is returned.
.TP
maketemp
fills in a string of XXXXX in its argument with the current process id.
.TP
errprint
prints its argument
on the diagnostic output file.
.TP
dumpdef
prints current names and definitions,
for the named items, or for all if no arguments are given.
.dt
.SH "SEE ALSO"
B. W. Kernighan and D. M. Ritchie,
.I The M4 Macro Processor
Commit	Line	Data
e6817382 BJ	1	.TH M4 1
	2	.SH NAME
	3	m4 \- macro processor
	4	.SH SYNOPSIS
	5	.B m4
	6	[ files ]
	7	.SH DESCRIPTION
	8	.I M4
	9	is a macro processor
	10	intended as a front end for Ratfor, C, and other languages.
	11	Each of the argument files is processed in order;
	12	if there are no arguments, or if an argument is `\-',
	13	the standard input is read.
	14	The processed text is written on the standard output.
	15	.PP
	16	Macro calls
	17	have the form
	18	.PP
	19	name(arg1,arg2, . . . , argn)
	20	.br
	21	.PP
	22	The `(' must immediately follow the name of the macro.
	23	If a defined macro name is not followed by a `(',
	24	it is deemed to have no arguments.
	25	Leading unquoted blanks, tabs, and newlines are ignored while collecting arguments.
	26	Potential macro names consist of alphabetic letters,
	27	digits, and underscore `\_', where the first character is not a digit.
	28	.PP
	29	Left and right single quotes (\`\\|\') are used to quote strings.
	30	The value of a quoted string is the string stripped of the quotes.
	31	.PP
	32	When a macro name is recognized,
	33	its arguments are collected by searching for a matching right
	34	parenthesis.
	35	Macro evaluation proceeds normally during the collection of the arguments,
	36	and any commas or right parentheses
	37	which happen to turn up within the value of a nested
	38	call are as effective as those in the original input text.
	39	After argument collection,
	40	the value of the macro is pushed back onto the input stream
	41	and rescanned.
	42	.PP
	43	.I M4
	44	makes available the following built-in macros.
	45	They may be redefined, but once this is done the original meaning is lost.
	46	Their values are null unless otherwise stated.
	47	.TP 10
	48	define
	49	The second argument is installed as the value of the macro
	50	whose name is the first argument.
	51	Each occurrence of $\fIn\fR in the replacement text,
	52	where
	53	.I n
	54	is a digit,
	55	is replaced by the
	56	.IR n -th
	57	argument.
	58	Argument 0 is the name of the macro;
	59	missing arguments are replaced by the null string.
	60	.TP
	61	undefine
	62	removes the definition of the macro named in its argument.
	63	.TP
	64	ifdef
65	If the first argument is defined, the value is the second argument, otherwise the third.
66	If there is no third argument, the value is null.
67	The word
68	.I unix
69	is predefined on UNIX versions of
70	.IR m4 .
71	.TP
72	changequote
73	Change quote characters to the first and second arguments.
74	.I Changequote
75	without arguments restores the original values
76	(i.e., \`\\|\').
77	.TP
78	divert
79	.I M4
80	maintains 10 output streams,
81	numbered 0-9.
82	The final output is the concatenation of the streams
83	in numerical order;
84	initially stream 0 is the current stream.
85	The
86	.I divert
87	macro changes the current output stream to its (digit-string)
88	argument.
89	Output diverted to a stream other than 0 through 9
90	is discarded.
91	.TP
92	undivert
93	causes immediate output of text from diversions named as
94	arguments, or all diversions if no argument.
95	Text may be undiverted into another diversion.
96	Undiverting discards the diverted text.
97	.TP
98	divnum
99	returns the value of the current output stream.
100	.TP
101	dnl
102	reads and discards characters up to and including the next newline.
103	.TP
104	ifelse
105	has three or more arguments.
106	If the first argument is the same string as the second,
107	then the value is the third argument.
108	If not, and if there are more than four arguments, the process is repeated with arguments 4, 5, 6 and 7.
109	Otherwise, the value is either the fourth string, or, if it is not present,
110	null.
111	.TP
112	incr
113	returns the value of its argument incremented by 1.
114	The value of the argument is calculated
115	by interpreting an initial digit-string as a decimal number.
116	.TP
117	eval
118	evaluates its argument as an arithmetic expression, using 32-bit arithmetic.
119	Operators include +, \-, \(**, /, %, ^ (exponentiation); relationals; parentheses.
120	.TP
121	len
122	returns the number of characters in its argument.
123	.TP
124	index
125	returns the position in its first argument where the second argument begins (zero origin),
126	or \-1 if the second argument does not occur.
127	.TP
128	substr
129	returns a substring of its first argument.
130	The second argument is a zero origin
131	number selecting the first character;
132	the third argument indicates the length of the substring.
133	A missing third argument is taken to be large enough to extend to
134	the end of the first string.
135	.TP
136	translit
137	transliterates the characters in its first argument
138	from the set given by the second argument to the set given by the third.
139	No abbreviations are permitted.
140	.TP
141	include
142	returns the contents of the file named in the argument.
143	.TP
144	sinclude
145	is identical to
146	.I include,
147	except that it
148	says nothing if the file is inaccessible.
149	.TP
150	syscmd
151	executes the UNIX command given in the first argument.
152	No value is returned.
153	.TP
154	maketemp
155	fills in a string of XXXXX in its argument with the current process id.
156	.TP
157	errprint
158	prints its argument
159	on the diagnostic output file.
160	.TP
161	dumpdef
162	prints current names and definitions,
163	for the named items, or for all if no arguments are given.
164	.dt
165	.SH "SEE ALSO"
166	B. W. Kernighan and D. M. Ritchie,
167	.I The M4 Macro Processor