diff options
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index 9c9ea11c73..02a1655099 100644 --- a/configure.ac +++ b/configure.ac @@ -1658,6 +1658,26 @@ AC_CHECK_SIZEOF(socklen_t, , [AC_INCLUDES_DEFAULT() AC_CHECK_SIZEOF(cell_t) +# Let's see if stdatomic works. (There are some debian clangs that screw it +# up; see Tor bug #26779 and debian bug 903709.) +AC_CACHE_CHECK([whether C11 stdatomic.h actually works], + tor_cv_stdatomic_works, +[AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ +#include <stdatomic.h> +struct x { atomic_size_t y; }; +void try_atomic_init(struct x *xx) +{ + atomic_init(&xx->y, 99); + atomic_fetch_add(&xx->y, 1); +} +]])], [tor_cv_stdatomic_works=yes], [tor_cv_stdatomic_works=no])]) + +if test "$tor_cv_stdatomic_works" = "yes"; then + AC_DEFINE(STDATOMIC_WORKS, 1, [Set to 1 if we can compile a simple stdatomic example.]) +elif test "$ac_cv_header_stdatomic_h" = "yes"; then + AC_MSG_WARN([Your compiler provides the stdatomic.h header, but it doesn't seem to work. I'll pretend it isn't there. If you are using Clang on Debian, maybe this is because of https://bugs.debian.org/903709 ]) +fi + # Now make sure that NULL can be represented as zero bytes. AC_CACHE_CHECK([whether memset(0) sets pointers to NULL], tor_cv_null_is_zero, [AC_RUN_IFELSE([AC_LANG_SOURCE( |