1# serial 27 2 3# Copyright (C) 2001-2003, 2005, 2007, 2009-2020 Free Software Foundation, Inc. 4# This file is free software; the Free Software Foundation 5# gives unlimited permission to copy and/or distribute it, 6# with or without modifications, as long as this notice is preserved. 7 8dnl From Jim Meyering. 9 10AC_DEFUN([gl_FUNC_GETTIMEOFDAY], 11[ 12 AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS]) 13 AC_REQUIRE([AC_C_RESTRICT]) 14 AC_REQUIRE([AC_CANONICAL_HOST]) 15 AC_REQUIRE([gl_HEADER_SYS_TIME_H]) 16 AC_CHECK_FUNCS_ONCE([gettimeofday]) 17 18 gl_gettimeofday_timezone=void 19 if test $ac_cv_func_gettimeofday != yes; then 20 HAVE_GETTIMEOFDAY=0 21 else 22 gl_FUNC_GETTIMEOFDAY_CLOBBER 23 AC_CACHE_CHECK([for gettimeofday with POSIX signature], 24 [gl_cv_func_gettimeofday_posix_signature], 25 [AC_COMPILE_IFELSE( 26 [AC_LANG_PROGRAM( 27 [[#include <sys/time.h> 28 struct timeval c; 29 int gettimeofday (struct timeval *restrict, void *restrict); 30 ]], 31 [[/* glibc uses struct timezone * rather than the POSIX void * 32 if _GNU_SOURCE is defined. However, since the only portable 33 use of gettimeofday uses NULL as the second parameter, and 34 since the glibc definition is actually more typesafe, it is 35 not worth wrapping this to get a compliant signature. */ 36 int (*f) (struct timeval *restrict, void *restrict) 37 = gettimeofday; 38 int x = f (&c, 0); 39 return !(x | c.tv_sec | c.tv_usec); 40 ]])], 41 [gl_cv_func_gettimeofday_posix_signature=yes], 42 [AC_COMPILE_IFELSE( 43 [AC_LANG_PROGRAM( 44 [[#include <sys/time.h> 45int gettimeofday (struct timeval *restrict, struct timezone *restrict); 46 ]])], 47 [gl_cv_func_gettimeofday_posix_signature=almost], 48 [gl_cv_func_gettimeofday_posix_signature=no])])]) 49 if test $gl_cv_func_gettimeofday_posix_signature = almost; then 50 gl_gettimeofday_timezone='struct timezone' 51 elif test $gl_cv_func_gettimeofday_posix_signature != yes; then 52 REPLACE_GETTIMEOFDAY=1 53 fi 54 dnl If we override 'struct timeval', we also have to override gettimeofday. 55 if test $REPLACE_STRUCT_TIMEVAL = 1; then 56 REPLACE_GETTIMEOFDAY=1 57 fi 58 dnl On mingw, the original gettimeofday has only a precision of 15.6 59 dnl milliseconds. So override it. 60 case "$host_os" in 61 mingw*) REPLACE_GETTIMEOFDAY=1 ;; 62 esac 63 fi 64 AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone], 65 [Define this to 'void' or 'struct timezone' to match the system's 66 declaration of the second argument to gettimeofday.]) 67]) 68 69 70dnl See if gettimeofday clobbers the static buffer that localtime uses 71dnl for its return value. The gettimeofday function from Mac OS X 10.0.4 72dnl (i.e., Darwin 1.3.7) has this problem. 73dnl 74dnl If it does, then arrange to use gettimeofday and localtime only via 75dnl the wrapper functions that work around the problem. 76 77AC_DEFUN([gl_FUNC_GETTIMEOFDAY_CLOBBER], 78[ 79 AC_REQUIRE([gl_HEADER_SYS_TIME_H]) 80 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles 81 AC_REQUIRE([gl_LOCALTIME_BUFFER_DEFAULTS]) 82 83 AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer], 84 [gl_cv_func_gettimeofday_clobber], 85 [AC_RUN_IFELSE( 86 [AC_LANG_PROGRAM( 87 [[#include <string.h> 88 #include <sys/time.h> 89 #include <time.h> 90 #include <stdlib.h> 91 ]], 92 [[ 93 time_t t = 0; 94 struct tm *lt; 95 struct tm saved_lt; 96 struct timeval tv; 97 lt = localtime (&t); 98 saved_lt = *lt; 99 gettimeofday (&tv, NULL); 100 return memcmp (lt, &saved_lt, sizeof (struct tm)) != 0; 101 ]])], 102 [gl_cv_func_gettimeofday_clobber=no], 103 [gl_cv_func_gettimeofday_clobber=yes], 104 [# When cross-compiling: 105 case "$host_os" in 106 # Guess all is fine on glibc systems. 107 *-gnu* | gnu*) gl_cv_func_gettimeofday_clobber="guessing no" ;; 108 # Guess all is fine on musl systems. 109 *-musl*) gl_cv_func_gettimeofday_clobber="guessing no" ;; 110 # Guess no on native Windows. 111 mingw*) gl_cv_func_gettimeofday_clobber="guessing no" ;; 112 # If we don't know, obey --enable-cross-guesses. 113 *) gl_cv_func_gettimeofday_clobber="$gl_cross_guess_inverted" ;; 114 esac 115 ])]) 116 117 case "$gl_cv_func_gettimeofday_clobber" in 118 *yes) 119 REPLACE_GETTIMEOFDAY=1 120 AC_DEFINE([GETTIMEOFDAY_CLOBBERS_LOCALTIME], [1], 121 [Define if gettimeofday clobbers the localtime buffer.]) 122 gl_LOCALTIME_BUFFER_NEEDED 123 ;; 124 esac 125]) 126 127# Prerequisites of lib/gettimeofday.c. 128AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [:]) 129