diff doc/posix-functions/alarm.texi @ 17366:9855b352e525

regex: port to mingw's recent addition of undeclared alarm On mingw (at least, when cross-compiling with Fedora 18's mingw32-headers-2.0.999-0.15.trunk.20121110.fc18.noarch build), compilation of test-regex fails: test-regex.c: In function 'main': test-regex.c:42:11: error: 'SIGALRM' undeclared (first use in this function) test-regex.c:42:11: note: each undeclared identifier is reported only once for each function it appears in test-regex.c:43:3: warning: implicit declaration of function 'alarm' It turns out that recent mingw64 added an export of alarm() and SIGALRM, but guarded their declarations behind __USE_MINGW_ALARM (default off, and with alarm() only in the non-standard <io.h>); so the m4 tests were setting HAVE_ALARM to 1 based on link success but then failing to compile. * doc/posix-functions/alarm.texi (alarm): Document that alarm exists but still doesn't work in newer mingw. * m4/frexp.m4 (gl_FUNC_FREXP_WORKS): Check for alarm declaration, not existence. Ensure SIGALRM is not trapped. * m4/mktime.m4 (gl_FUNC_MKTIME): Likewise. * m4/regex.m4 (gl_REGEX): Likewise. * m4/remainderf.m4 (gl_FUNC_REMAINDERF_WORKS): Likewise. * tests/test-regex.c (main): Use correct probe for alarm. Signed-off-by: Eric Blake <eblake@redhat.com>
author Eric Blake <eblake@redhat.com>
date Mon, 11 Mar 2013 14:51:33 -0600
parents 6355dc4626b5
children
line wrap: on
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--- a/doc/posix-functions/alarm.texi
+++ b/doc/posix-functions/alarm.texi
@@ -13,6 +13,16 @@
 Portability problems not fixed by Gnulib:
 @itemize
 @item
+This function has no impact if <code>SIGALRM</code> is inherited as
+ignored; programs should use <code>signal (SIGALRM, SIG_DFL)</code> if
+it is important to ensure the alarm will fire.
+@item
+Use of this function in multi-threaded applications is not advised.
+@item
 This function is missing on some platforms:
-mingw, MSVC 9.
+mingw (2011), MSVC 9.
+@item
+This function is conditionally declared in the non-standard
+@code{<io.h>} header on some platforms:
+mingw (2012 or newer).
 @end itemize