gettimeofday: expose type of second argument

[gnulib.git] / m4 / gettimeofday.m4

diff --git a/m4/gettimeofday.m4 b/m4/gettimeofday.m4
index 2155627..32e4f29 100644 (file)
--- a/m4/gettimeofday.m4
+++ b/m4/gettimeofday.m4
@@ -1,4 +1,4 @@
-# serial 13
+# serial 14
 
 # Copyright (C) 2001-2003, 2005, 2007, 2009-2010 Free Software Foundation, Inc.
 # This file is free software; the Free Software Foundation
@@ -14,30 +14,46 @@ AC_DEFUN([gl_FUNC_GETTIMEOFDAY],
   AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
   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
-    if test $gl_cv_func_gettimeofday_clobber != yes; then
+  gl_gettimeofday_timezone=void
+  if test $ac_cv_func_gettimeofday = yes; then
+    gl_FUNC_GETTIMEOFDAY_CLOBBER
+    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 gettimeofday (struct timeval *restrict, void *restrict);
+            ]],
+            [[/* glibc uses struct timezone * rather than the POSIX void *
+                 if _GNU_SOURCE is defined.  However, since the only portable
+                 use of gettimeofday uses NULL as the second parameter, and
+                 since the glibc definition is actually more typesafe, it is
+                 not worth wrapping this to get a compliant signature.  */
+              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],
+          [AC_COMPILE_IFELSE(
+            [AC_LANG_PROGRAM(
+              [[#include <sys/time.h>
+int gettimeofday (struct timeval *restrict, struct timezone *restrict);
+              ]])],
+            [gl_cv_func_gettimeofday_posix_signature=almost],
+            [gl_cv_func_gettimeofday_posix_signature=no])])])
+    if test $gl_cv_func_gettimeofday_posix_signature = almost; then
+      gl_gettimeofday_timezone='struct timezone'
+    elif test $gl_cv_func_gettimeofday_posix_signature != yes; then
+      REPLACE_GETTIMEOFDAY=1
       AC_LIBOBJ([gettimeofday])
       gl_PREREQ_GETTIMEOFDAY
     fi
   fi
+  AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone],
+    [Define this to 'void' or 'struct timezone' to match the system's
+     declaration of the second argument to gettimeofday.])
 ])