Re: [libvirt] [PATCH 2/4] Require use of GCC 4.4 or CLang compilers

We only ever test libvirt with GCC or CLang which provides a GCC compatible compilation environment. Between them, these compilers cover every important operating system platform, even Windows. Mandate their use to make it explicit that we don't care about compilers like Microsoft VCC or other UNIX vendor C compilers. GCC 4.4 was picked as the baseline, since RHEL-6 ships 4.4.7 and that lets us remove a large set of checks. There is a slight issue that CLang reports itself as GCC 4.2, so we must also check if __clang__ is defined. We could check a particular CLang version too, but that would require someone to figure out a suitable min version which is fun because OS-X reports totally different CLang version numbers from CLang builds on Linux/BSD Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- config-post.h | 20 +++++----- src/internal.h | 116 ++++++++++++++++----------------------------------------- 2 files changed, 44 insertions(+), 92 deletions(-) diff --git a/config-post.h b/config-post.h index 75e7d02..4bddbac 100644 --- a/config-post.h +++ b/config-post.h @@ -74,6 +74,10 @@ # undef WITH_CAPNG #endif /* LIBVIRT_NSS */ +#ifndef __GNUC__ +# error "Libvirt requires GCC >= 4.4, or CLang" +#endif + /* * Define __GNUC_PREREQ to a sane default if it isn't yet defined. * This is done here so that it's included as early as possible; gnulib relies @@ -81,13 +85,11 @@ * This doesn't happen on many non-glibc systems. * When __GNUC_PREREQ is not defined, gnulib defines it to 0, which breaks things. */ -#ifdef __GNUC__ -# ifndef __GNUC_PREREQ -# if defined __GNUC__ && defined __GNUC_MINOR__ -# define __GNUC_PREREQ(maj, min) \ - ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) -# else -# define __GNUC_PREREQ(maj, min) 0 -# endif -# endif +#ifndef __GNUC_PREREQ +# define __GNUC_PREREQ(maj, min) \ + ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min)) +#endif + +#if !__GNUC_PREREQ(4, 4) || defined(__clang__)

+# error "Libvirt requires GCC >= 4.4, or CLang" #endif