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) 12/14/88

unifdef - remove ifdef'ed lines unifdef [ -t -l -c -Dsym -Usym -iDsym -iDsym ] ... [ file ] Unifdef is useful for removing ifdef'ed lines from a file while otherwise leaving the file alone. Unifdef 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.

If you want to use unifdef for plain text (not C code), use the -t option, which disables this parsing for C comments and quotes.

You specify which symbols you want defined (-Dsym) or undefined (-Usym) 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 sym 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.

The -l option causes unifdef to replace removed lines with blank lines instead of deleting them.

If your C code uses ifdefs to delimit non-C lines, such as comments or code which is under construction, then you must tell unifdef 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 -iDsym and -iUsym similar to -Dsym and -Usym above.

Unifdef copies its output to stdout and will take its input from stdin if no file argument is given. If the -c argument is specified, then the operation of unifdef is complemented, i.e. the lines that would have been removed or blanked are retained and vice versa.

Unifdef works nicely with the -Dsym option added to diff(1) as of the 4.1 Berkeley Software Distribution.

diff(1) Inappropriate else or endif.

Premature EOF with line numbers of the unterminated #ifdefs.

Exit status is 0 if output is exact copy of input, 1 if not, 2 if trouble.

Dave Yost for The Rand Corporation.

Still maintained independently by Dave Yost as of 3/85

Should try to deal with ``#if'' lines.

Doesn't work correctly if input contains null characters.