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Re: failed config.h substitution
From: |
Akim Demaille |
Subject: |
Re: failed config.h substitution |
Date: |
29 Oct 2002 14:07:25 +0100 |
User-agent: |
Gnus/5.0808 (Gnus v5.8.8) XEmacs/21.4 (Honest Recruiter) |
| Hi,
| autoconf-2.52 doesn't substitute #undef's if they are followed by a comment
| in the config.h.in. This is
| 1. a regression versus autoconf-2.13.
| 2. not documented in the manual.
| Thus it looks like a bug.
Yes, you are right. I'm installing the following:
Index: ChangeLog
from Akim Demaille <address@hidden>
* doc/autoconf.texi (Header Templates): Put also in words what the
pictures says to assist free style readers.
Index: doc/autoconf.texi
===================================================================
RCS file: /cvsroot/autoconf/autoconf/doc/autoconf.texi,v
retrieving revision 1.704
diff -u -u -r1.704 autoconf.texi
--- doc/autoconf.texi 29 Oct 2002 12:41:16 -0000 1.704
+++ doc/autoconf.texi 29 Oct 2002 13:04:01 -0000
@@ -2471,8 +2471,9 @@
Then you could have code like the following in @file{conf.h.in}. On
systems that have @file{unistd.h}, @command{configure} will @samp{#define}
@samp{HAVE_UNISTD_H} to 1. On other systems, the whole line will be
commented out (in case the system predefines that symbol).
@example
@group
/* Define as 1 if you have unistd.h. */
#undef HAVE_UNISTD_H
@end group
@end example
-You can then decode the configuration header using the preprocessor
-directives:
+Pay attention that @samp{#undef} is in the first column, and there is
+nothing behind @samp{HAVE_UNISTD_H}, not even white spaces. You can
+then decode the configuration header using the preprocessor directives:
@example
@group
@@ -2487,7 +2488,9 @@
@end example
The use of old form templates, with @samp{#define} instead of
address@hidden is strongly discouraged.
address@hidden is strongly discouraged. Similarly with old templates
+with comments on the same line as the @samp{#undef}. Anyway, putting
+comments in preprocessor macros has never been a good idea.
Since it is a tedious task to keep a template header up to date, you may
use @command{autoheader} to generate it, see @ref{autoheader Invocation}.