diff options
Diffstat (limited to 'configure.in')
| -rw-r--r-- | configure.in | 32 |
1 files changed, 31 insertions, 1 deletions
diff --git a/configure.in b/configure.in index ea656331423..98243750ca6 100644 --- a/configure.in +++ b/configure.in @@ -1259,7 +1259,37 @@ AC_FUNC_ALLOCA AC_CHECK_LIB(m, sqrt(0.0) + t) AC_CHECK_FUNCS(gettimeofday gethostname dup2 rename closedir mkdir rmdir \ random lrand48 bcopy bcmp logb frexp fmod drem ftime res_init setsid \ -strerror fpathconf select mktime eaccess getpagesize) +strerror fpathconf select mktime eaccess getpagesize tzset) + +AC_MSG_CHECKING(whether localtime caches TZ) +AC_CACHE_VAL(emacs_cv_localtime_cache, +[if test $ac_cv_func_tzset = yes; then +AC_TRY_RUN([#include <time.h> +#if STDC_HEADERS +# include <stdlib.h> +#endif +main() +{ + time_t now = time ((time_t *) 0); + int hour; + if (putenv ("TZ=GMT0") != 0) + exit (1); + hour = localtime (&now)->tm_hour; + if (putenv ("TZ=PST8") != 0) + exit (1); + exit (localtime (&now)->tm_hour == hour); +}], emacs_cv_localtime_cache=no, emacs_cv_localtime_cache=yes, +[# If we have tzset, assume the worst when cross-compiling. +emacs_cv_localtime_cache=yes]) +else + # If we lack tzset, report that localtime does not cache TZ, + # since we can't invalidate the cache if we don't have tzset. + emacs_cv_localtime_cache=no +fi])dnl +AC_MSG_RESULT($emacs_cv_localtime_cache) +if test $emacs_cv_localtime_cache = yes; then + AC_DEFINE(LOCALTIME_CACHE) +fi if test $HAVE_TIMEVAL = yes; then AC_MSG_CHECKING(whether gettimeofday can't accept two arguments) |