From 9f7f1ac18d19ba0b1b6efcdcae037fca237e5534 Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Wed, 22 Jan 1997 22:38:37 +0000 Subject: [PATCH] (AM_FUNC_MKTIME): Fix bug in mktime test -- don't test now, test a couple of thousand times. --- m4/mktime.m4 | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) diff --git a/m4/mktime.m4 b/m4/mktime.m4 index 3f03b1e0c4..c0fcf198bd 100644 --- a/m4/mktime.m4 +++ b/m4/mktime.m4 @@ -5,7 +5,8 @@ AC_DEFUN(AM_FUNC_MKTIME, [AC_REQUIRE([AC_HEADER_TIME])dnl AC_CHECK_HEADERS(sys/time.h) AC_CACHE_CHECK([for working mktime], am_cv_func_working_mktime, - [AC_TRY_RUN([/* Test program from Tony Leneis (tony@plaza.ds.adp.com). */ + [AC_TRY_RUN([/* Test program from Paul Eggert (eggert@twinsun.com) + and Tony Leneis (tony@plaza.ds.adp.com). */ #if TIME_WITH_SYS_TIME # include # include @@ -16,12 +17,33 @@ AC_DEFUN(AM_FUNC_MKTIME, # include # endif #endif + +static time_t time_t_max; + +static void +mktime_test (now) + time_t now; +{ + if (mktime (localtime (&now)) != now) + exit (1); + now = time_t_max - now; + if (mktime (localtime (&now)) != now) + exit (1); +} + int main () { - time_t today = time (0); - struct tm *local = localtime (&today); - exit (mktime (local) != today); + time_t t, delta; + for (time_t_max = 1; 0 < time_t_max; time_t_max *= 2) + continue; + time_t_max--; + delta = time_t_max / 997; /* a suitable prime number */ + for (t = 0; t <= time_t_max - delta; t += delta) + mktime_test (t); + mktime_test ((time_t) 60 * 60); + mktime_test ((time_t) 60 * 60 * 24); + exit (0); } ], am_cv_func_working_mktime=yes, am_cv_func_working_mktime=no, -- 2.30.2