1 files changed, 101 insertions, 0 deletions
diff --git a/m4/gettimeofday.m4 b/m4/gettimeofday.m4
new file mode 100644
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--- /dev/null
+++ b/m4/gettimeofday.m4
@@ -0,0 +1,101 @@
+# serial 12
+
+# Copyright (C) 2001-2003, 2005, 2007, 2009 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+
+AC_DEFUN([gl_FUNC_GETTIMEOFDAY],
+[
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H])
+  AC_CHECK_FUNCS_ONCE([gettimeofday])
+
+  AC_CACHE_CHECK([for gettimeofday with POSIX signature],
+    [gl_cv_func_gettimeofday_posix_signature],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+	  [[#include <sys/time.h>
+	    struct timeval c;
+	  ]],
+	  [[
+	    int (*f) (struct timeval *restrict, void *restrict) = gettimeofday;
+	    int x = f (&c, 0);
+	    return !(x | c.tv_sec | c.tv_usec);
+	  ]])],
+	[gl_cv_func_gettimeofday_posix_signature=yes],
+	[gl_cv_func_gettimeofday_posix_signature=no])])
+
+  gl_FUNC_GETTIMEOFDAY_CLOBBER
+
+  if test $gl_cv_func_gettimeofday_posix_signature != yes; then
+    REPLACE_GETTIMEOFDAY=1
+    SYS_TIME_H=sys/time.h
+    if test $gl_cv_func_gettimeofday_clobber != yes; then
+      AC_LIBOBJ([gettimeofday])
+      gl_PREREQ_GETTIMEOFDAY
+    fi
+  fi
+])
+
+
+dnl See if gettimeofday clobbers the static buffer that localtime uses
+dnl for its return value.  The gettimeofday function from Mac OS X 10.0.4
+dnl (i.e., Darwin 1.3.7) has this problem.
+dnl
+dnl If it does, then arrange to use gettimeofday and localtime only via
+dnl the wrapper functions that work around the problem.
+
+AC_DEFUN([gl_FUNC_GETTIMEOFDAY_CLOBBER],
+[
+ AC_REQUIRE([gl_HEADER_SYS_TIME_H])
+
+ AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer],
+  [gl_cv_func_gettimeofday_clobber],
+  [AC_RUN_IFELSE(
+     [AC_LANG_PROGRAM(
+	[[#include <string.h>
+	  #include <sys/time.h>
+	  #include <time.h>
+	  #include <stdlib.h>
+	]],
+	[[
+	  time_t t = 0;
+	  struct tm *lt;
+	  struct tm saved_lt;
+	  struct timeval tv;
+	  lt = localtime (&t);
+	  saved_lt = *lt;
+	  gettimeofday (&tv, NULL);
+	  return memcmp (lt, &saved_lt, sizeof (struct tm)) != 0;
+	]])],
+     [gl_cv_func_gettimeofday_clobber=no],
+     [gl_cv_func_gettimeofday_clobber=yes],
+     dnl When crosscompiling, assume it is broken.
+     [gl_cv_func_gettimeofday_clobber=yes])])
+
+ if test $gl_cv_func_gettimeofday_clobber = yes; then
+   REPLACE_GETTIMEOFDAY=1
+   SYS_TIME_H=sys/time.h
+   gl_GETTIMEOFDAY_REPLACE_LOCALTIME
+   AC_DEFINE([GETTIMEOFDAY_CLOBBERS_LOCALTIME], [1],
+     [Define if gettimeofday clobbers the localtime buffer.])
+ fi
+])
+
+AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [
+  AC_LIBOBJ([gettimeofday])
+  gl_PREREQ_GETTIMEOFDAY
+  AC_DEFINE([gmtime], [rpl_gmtime],
+    [Define to rpl_gmtime if the replacement function should be used.])
+  AC_DEFINE([localtime], [rpl_localtime],
+    [Define to rpl_localtime if the replacement function should be used.])
+])
+
+# Prerequisites of lib/gettimeofday.c.
+AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [
+  AC_CHECK_HEADERS([sys/timeb.h])
+  AC_CHECK_FUNCS([_ftime])
+])