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According to Eric Blake on 3/20/2009 6:30 AM:
>> $ find /usr/include | xargs grep sig_atomic_t
>> /usr/include/sys/signal.h:typedef volatile int sig_atomic_t;
>
> Therefore, 'volatile sig_atomic_t' is not a bug, even if sig_atomic_t
> already included volatile in its typedef. So the real solution here is to
> enhance a .m4 test to detect your compiler's bug in refusing to compile
> something that the C standard requires, and write a gnulib replacement
> <sys/types.h> and/or <signal.h> that does:
<sys/types.h> would be the wrong place to add it; POSIX only requires its
definition in <signal.h>. And that is fortunate, since gnulib has not yet
tackled sys/types but does have signal.in.h already. Does the first patch
solve things for you?
$ git pull git://repo.or.cz/gnulib/ericb.git master
I blindly chose int for sig_atomic_t. I suppose there is a chance that
this is the wrong type for some platform, in which case test-stdint should
catch that, and we can revisit how to coordinate between the signal and
stdint which size and signedness to use for sig_atomic_t. Meanwhile, I
added a signal-tests module as a basic smoke test as the second patch.
Any review or objections before I push this to savannah?
- --
Don't work too hard, make some time for fun as well!
Eric Blake e...@byu.net
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From b4cfd66ecb0093c466589ce4274bbdfc7178149c Mon Sep 17 00:00:00 2001
From: Eric Blake <e...@byu.net>
Date: Sat, 21 Mar 2009 17:57:40 -0600
Subject: [PATCH 1/2] signal.h: always support 'volatile sig_atomic_t'
* m4/signal_h.m4 (gl_SIGNAL_H): Check for AIX limitation.
(gl_SIGNAL_H_DEFAULTS): Add a default.
* modules/signal (Makefile.am): Substitute if needed.
* lib/signal.in.h (sig_atomic_t): Redefine if needed, so that
users can blindly add volatile.
* doc/posix-headers/signal.texi (signal.h): Document it.
Reported by Matthew Woehlke.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 11 +++++++++++
doc/posix-headers/signal.texi | 4 ++++
lib/signal.in.h | 11 ++++++++++-
m4/signal_h.m4 | 12 ++++++++++--
modules/signal | 1 +
5 files changed, 36 insertions(+), 3 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 4a23101..d0030b3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2009-03-21 Eric Blake <e...@byu.net>
+
+ signal.h: always support 'volatile sig_atomic_t'
+ * m4/signal_h.m4 (gl_SIGNAL_H): Check for AIX limitation.
+ (gl_SIGNAL_H_DEFAULTS): Add a default.
+ * modules/signal (Makefile.am): Substitute if needed.
+ * lib/signal.in.h (sig_atomic_t): Redefine if needed, so that
+ users can blindly add volatile.
+ * doc/posix-headers/signal.texi (signal.h): Document it.
+ Reported by Matthew Woehlke.
+
2009-03-20 Bruno Haible <br...@clisp.org>
Make sockets.h self-contained.
diff --git a/doc/posix-headers/signal.texi b/doc/posix-headers/signal.texi
index 860a79d..05be64b 100644
--- a/doc/posix-headers/signal.texi
+++ b/doc/posix-headers/signal.texi
@@ -8,6 +8,10 @@ Gnulib module: signal
Portability problems fixed by Gnulib:
@itemize
@item
+...@code{volatile sig_atomic_t} is rejected by older compilers on some
+platforms:
+AIX.
+...@item
@code{sigset_t} is only declared in <sys/types.h> on some platforms:
mingw.
@item
diff --git a/lib/signal.in.h b/lib/signal.in.h
index 3c74fd8..5c42fe9 100644
--- a/lib/signal.in.h
+++ b/lib/signal.in.h
@@ -1,6 +1,6 @@
/* A GNU-like <signal.h>.
- Copyright (C) 2006-2008 Free Software Foundation, Inc.
+ Copyright (C) 2006-2009 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
@@ -41,6 +41,15 @@
Also, mingw defines sigset_t not in <signal.h>, but in <sys/types.h>. */
#include <sys/types.h>
+/* On AIX, sig_atomic_t already includes volatile. C99 requires that
+ 'volatile sig_atomic_t' ignore the extra modifier, but C89 did not.
+ Hence, redefine this to a non-volatile type as needed. */
+#if ! @HAVE_TYPE_VOLATILE_SIG_ATOMIC_T@
+typedef int rpl_sig_atomic_t;
+# undef sig_atomic_t
+# define sig_atomic_t rpl_sig_atomic_t
+#endif
+
#ifdef __cplusplus
extern "C" {
#endif
diff --git a/m4/signal_h.m4 b/m4/signal_h.m4
index 4ac2e04..35534f4 100644
--- a/m4/signal_h.m4
+++ b/m4/signal_h.m4
@@ -1,5 +1,5 @@
-# signal_h.m4 serial 6
-dnl Copyright (C) 2007, 2008 Free Software Foundation, Inc.
+# signal_h.m4 serial 7
+dnl Copyright (C) 2007, 2008, 2009 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
@@ -8,6 +8,12 @@ AC_DEFUN([gl_SIGNAL_H],
[
AC_REQUIRE([gl_SIGNAL_H_DEFAULTS])
gl_CHECK_NEXT_HEADERS([signal.h])
+dnl AIX declares sig_atomic_t to already include volatile, and C89 compilers
+# then choke on 'volatile sig_atomic_t'. C99 requires that it compile.
+ AC_CHECK_TYPE([volatile sig_atomic_t], [],
+ [HAVE_TYPE_VOLATILE_SIG_ATOMIC_T=0], [[
+#include <signal.h>
+ ]])
])
AC_DEFUN([gl_SIGNAL_MODULE_INDICATOR],
@@ -29,4 +35,6 @@ AC_DEFUN([gl_SIGNAL_H_DEFAULTS],
HAVE_SIGACTION=1; AC_SUBST([HAVE_SIGACTION])
HAVE_STRUCT_SIGACTION_SA_SIGACTION=1;
AC_SUBST([HAVE_STRUCT_SIGACTION_SA_SIGACTION])
+ HAVE_TYPE_VOLATILE_SIG_ATOMIC_T=1;
+ AC_SUBST([HAVE_TYPE_VOLATILE_SIG_ATOMIC_T])
])
diff --git a/modules/signal b/modules/signal
index 5afb24f..bfef96f 100644
--- a/modules/signal
+++ b/modules/signal
@@ -31,6 +31,7 @@ signal.h: signal.in.h
-e 's|@''HAVE_SIGINFO_T''@|$(HAVE_SIGINFO_T)|g' \
-e 's|@''HAVE_SIGACTION''@|$(HAVE_SIGACTION)|g' \
-e
's|@''HAVE_STRUCT_SIGACTION_SA_SIGACTION''@|$(HAVE_STRUCT_SIGACTION_SA_SIGACTION)|g'
\
+ -e
's|@''HAVE_TYPE_VOLATILE_SIG_ATOMIC_T''@|$(HAVE_TYPE_VOLATILE_SIG_ATOMIC_T)|g' \
-e '/definition of GL_LINK_WARNING/r $(LINK_WARNING_H)' \
< $(srcdir)/signal.in.h; \
} > $...@-t
--
1.6.1.2
From e0ac25e195cdf7f5e7dea00167eef7eec5e52fe7 Mon Sep 17 00:00:00 2001
From: Eric Blake <e...@byu.net>
Date: Sat, 21 Mar 2009 18:26:52 -0600
Subject: [PATCH 2/2] signal-tests: test previous patch
* tests/test-signal.c: New file.
* modules/signal-tests: Likewise.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 4 ++++
modules/signal-tests | 13 +++++++++++++
tests/test-signal.c | 28 ++++++++++++++++++++++++++++
3 files changed, 45 insertions(+), 0 deletions(-)
create mode 100644 modules/signal-tests
create mode 100644 tests/test-signal.c
diff --git a/ChangeLog b/ChangeLog
index d0030b3..def2b4e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
2009-03-21 Eric Blake <e...@byu.net>
+ signal-tests: test previous patch
+ * tests/test-signal.c: New file.
+ * modules/signal-tests: Likewise.
+
signal.h: always support 'volatile sig_atomic_t'
* m4/signal_h.m4 (gl_SIGNAL_H): Check for AIX limitation.
(gl_SIGNAL_H_DEFAULTS): Add a default.
diff --git a/modules/signal-tests b/modules/signal-tests
new file mode 100644
index 0000000..0686537
--- /dev/null
+++ b/modules/signal-tests
@@ -0,0 +1,13 @@
+Files:
+tests/test-signal.c
+
+Depends-on:
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-signal
+check_PROGRAMS += test-signal
+
+License:
+LGPL
diff --git a/tests/test-signal.c b/tests/test-signal.c
new file mode 100644
index 0000000..4bc13ab
--- /dev/null
+++ b/tests/test-signal.c
@@ -0,0 +1,28 @@
+/* Test of <signal.h> substitute.
+ Copyright (C) 2009 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Eric Blake <e...@byu.net>, 2009. */
+
+#include <config.h>
+
+#include <signal.h>
+
+volatile sig_atomic_t s;
+
+int main ()
+{
+ return s;
+}
--
1.6.1.2
