Re: [PATCH] Add configure check for _Static_assert()
From: Lucas De Marchi <hidden>
Date: 2013-08-29 03:55:04
Hi Thomas, On Wed, Aug 28, 2013 at 12:33 PM, Thomas Petazzoni [off-list ref] wrote:
Commit 8efede20ef ("Use _Static_assert") introduced the usage of
_Static_assert(). However, _Static_assert() is a fairly new thing,
since it was introduced only in gcc 4.6. In order to support olderWhat distro is still in gcc 4.6? Is it a LTS one?
quoted hunk ↗ jump to hunk
compilers, this patch adds a configure.in test that checks whether _Static_assert() is usable or not, and adjust the behavior of the assert_cc() macro accordingly. Signed-off-by: Thomas Petazzoni <redacted> --- configure.ac | 6 ++++++ libkmod/macro.h | 4 ++++ 2 files changed, 10 insertions(+)diff --git a/configure.ac b/configure.ac index 40e54cf..cbe12f3 100644 --- a/configure.ac +++ b/configure.ac@@ -52,6 +52,12 @@ AC_CHECK_MEMBERS([struct stat.st_mtim], [], [], [#include <sys/stat.h>]) # Check kernel headers AC_CHECK_HEADERS_ONCE([linux/module.h]) +AC_MSG_CHECKING([whether _Static_assert() is supported]) +AC_COMPILE_IFELSE( + [AC_LANG_SOURCE([[_Static_assert(1, "Test");]])], + [AC_DEFINE([HAVE_STATIC_ASSERT], [1], [Define is _Static_assert() is available]) + AC_MSG_RESULT([yes])], + [AC_MSG_RESULT([no])]) ##################################################################### # --with-diff --git a/libkmod/macro.h b/libkmod/macro.h index c6ba855..5992026 100644 --- a/libkmod/macro.h +++ b/libkmod/macro.h@@ -21,8 +21,12 @@ #include <stddef.h> +#if defined(HAVE_STATIC_ASSERT) #define assert_cc(expr) \ _Static_assert((expr), #expr) +#else +#define assert_cc(expr)
could you then define it similarly to what it was before then in this #else?
I think this would do it (totally untested) with the downside of an
ugly build error.
#define assert_cc(expr) \
do { (void) sizeof(char [1 - 2*!(expr)]); } while(0)
thanks
Lucas De Marchi