.\" Copyright (c) 1985 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Dave Yost.
.\"
.\" Redistribution and use in source and binary forms are permitted
.\" provided that the above copyright notice and this paragraph are
.\" duplicated in all such forms and that any documentation,
.\" advertising materials, and other materials related to such
.\" distribution and use acknowledge that the software was developed
.\" by the University of California, Berkeley.  The name of the
.\" University may not be used to endorse or promote products derived
.\" from this software without specific prior written permission.
.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
.\" WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
.\"
.\"	@(#)unifdef.1	6.3 (Berkeley) %G%
.\"
.TH UNIFDEF 1 ""
.SH NAME
unifdef \- remove ifdef'ed lines
.SH SYNOPSIS
\fBunifdef\fR
[
\fB\-t\fR
\fB\-l\fR
\fB\-c\fR
\fB\-D\fR\fIsym\fR 
\fB\-U\fR\fIsym\fR 
\fB\-iD\fR\fIsym\fR
\fB\-iD\fR\fIsym\fR
] ...  [ file ]
.SH DESCRIPTION
\fIUnifdef\fR is useful for removing ifdef'ed lines
from a file while otherwise leaving the file alone.
\fIUnifdef\fR acts on
#ifdef, #ifndef, #else, and #endif lines,
and it knows only enough about C
to know when one of these is inactive
because it is inside
a comment,
or a single or double quote.
Parsing for quotes is very simplistic:
when it finds an open quote,
it ignores everything (except escaped quotes)
until it finds a close quote, and
it will not complain if it gets
to the end of a line and finds no backslash for continuation.
.PP
If you want to use \fIunifdef\fR
for plain text (not C code),
use the \fB\-t\fR option,
which disables this parsing for
C comments and quotes.
.PP
You specify which symbols you want defined
(\fB\-D\fR\fIsym\fR)
or undefined
(\fB\-U\fR\fIsym\fR)
and the lines inside those ifdefs will be copied to the output or removed as
appropriate.
The ifdef, ifndef, else, and endif lines associated with
\fIsym\fR will also be removed.
Ifdefs involving symbols you don't specify
and ``#if'' control lines
are untouched and copied out
along with their associated
ifdef, else, and endif lines.
If an ifdef X occurs nested inside another ifdef X, then the
inside ifdef is treated as if it were an unrecognized symbol.
If the same symbol appears in more than one argument,
the last occurrence dominates.
.PP
The \fB\-l\fR option causes \fIunifdef\fR
to replace removed lines with blank lines
instead of deleting them.
.PP
If your C code uses ifdefs to delimit non-C lines,
such as comments
or code which is under construction,
then you must tell \fIunifdef\fR
which symbols are used for that purpose so that it won't try to parse
for quotes and comments
inside those ifdefs.
You specify ignored ifdefs with
\fB\-iD\fR\fIsym\fR
and
\fB\-iU\fR\fIsym\fR
similar to
\fB\-D\fR\fIsym\fR
and
\fB\-U\fR\fIsym\fR
above.
.PP
\fIUnifdef\fR copies its output to \fIstdout\fR
and will take its input from \fIstdin\fR
if no \fIfile\fR argument is given.
If the \fB\-c\fR argument is specified,
then the operation of \fIunifdef\fR is complemented,
i.e. the lines that would have been removed or blanked
are retained and vice versa.
.PP
\fIUnifdef\fR works nicely with the \fB\-D\fR\fIsym\fR option added
to \fIdiff\fR(1) as of the 4.1 Berkeley Software Distribution.
.SH "SEE ALSO"
diff(1)
.SH DIAGNOSTICS
Inappropriate else or endif.
.br
Premature EOF with line numbers of the unterminated #ifdefs.
.PP
Exit status is 0 if output is exact copy of input, 1 if not, 2 if trouble.
.SH AUTHOR
Dave Yost for The Rand Corporation.
.br
Still maintained independently by Dave Yost as of 3/85
.SH BUGS
Should try to deal with ``#if'' lines.
.br
Doesn't work correctly if input contains null characters.