diff options
Diffstat (limited to 'configure.ac')
| -rw-r--r-- | configure.ac | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index f047ab9027..6c4a0792fe 100644 --- a/configure.ac +++ b/configure.ac @@ -1033,6 +1033,30 @@ if test "$tor_cv_null_is_zero" != no; then [Define to 1 iff memset(0) sets pointers to NULL]) fi +AC_CACHE_CHECK([whether memset(0) sets doubles to 0.0], tor_cv_dbl0_is_zero, +[AC_RUN_IFELSE([AC_LANG_SOURCE( +[[#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#ifdef HAVE_STDDEF_H +#include <stddef.h> +#endif +int main () { double d1,d2; d1=0; memset(&d2,0,sizeof(d2)); +return memcmp(&d1,&d2,sizeof(d1))?1:0; }]])], + [tor_cv_dbl0_is_zero=yes], + [tor_cv_dbl0_is_zero=no], + [tor_cv_dbl0_is_zero=cross])]) + +if test "$tor_cv_dbl0_is_zero" = cross ; then + # Cross-compiling; let's hope that the target isn't raving mad. + AC_MSG_NOTICE([Cross-compiling: we'll assume that 0.0 can be represented as a sequence of 0-valued bytes.]) +fi + +if test "$tor_cv_dbl0_is_zero" != no; then + AC_DEFINE([DOUBLE_0_REP_IS_ZERO_BYTES], 1, + [Define to 1 iff memset(0) sets doubles to 0.0]) +fi + # And what happens when we malloc zero? AC_CACHE_CHECK([whether we can malloc(0) safely.], tor_cv_malloc_zero_works, [AC_RUN_IFELSE([AC_LANG_SOURCE( |