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Diffstat (limited to 'm4/gettimeofday.m4')
| -rw-r--r-- | m4/gettimeofday.m4 | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/m4/gettimeofday.m4 b/m4/gettimeofday.m4 new file mode 100644 index 0000000..198695e --- /dev/null +++ b/m4/gettimeofday.m4 @@ -0,0 +1,126 @@ +# serial 25 + +# Copyright (C) 2001-2003, 2005, 2007, 2009-2018 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([gl_HEADER_SYS_TIME_H_DEFAULTS]) + AC_REQUIRE([AC_C_RESTRICT]) + AC_REQUIRE([AC_CANONICAL_HOST]) + AC_REQUIRE([gl_HEADER_SYS_TIME_H]) + AC_CHECK_FUNCS_ONCE([gettimeofday]) + + gl_gettimeofday_timezone=void + if test $ac_cv_func_gettimeofday != yes; then + HAVE_GETTIMEOFDAY=0 + else + 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 + fi + dnl If we override 'struct timeval', we also have to override gettimeofday. + if test $REPLACE_STRUCT_TIMEVAL = 1; then + REPLACE_GETTIMEOFDAY=1 + fi + dnl On mingw, the original gettimeofday has only a precision of 15.6 + dnl milliseconds. So override it. + case "$host_os" in + mingw*) REPLACE_GETTIMEOFDAY=1 ;; + esac + fi + AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone], + [Define this to 'void' or 'struct timezone' to match the system's + declaration of the second argument to gettimeofday.]) +]) + + +dnl See if gettimeofday clobbers the static buffer that localtime uses +dnl for its return value. The gettimeofday function from Mac OS X 10.0.4 +dnl (i.e., Darwin 1.3.7) has this problem. +dnl +dnl If it does, then arrange to use gettimeofday and localtime only via +dnl the wrapper functions that work around the problem. + +AC_DEFUN([gl_FUNC_GETTIMEOFDAY_CLOBBER], +[ + AC_REQUIRE([gl_HEADER_SYS_TIME_H]) + AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles + AC_REQUIRE([gl_LOCALTIME_BUFFER_DEFAULTS]) + + AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer], + [gl_cv_func_gettimeofday_clobber], + [AC_RUN_IFELSE( + [AC_LANG_PROGRAM( + [[#include <string.h> + #include <sys/time.h> + #include <time.h> + #include <stdlib.h> + ]], + [[ + time_t t = 0; + struct tm *lt; + struct tm saved_lt; + struct timeval tv; + lt = localtime (&t); + saved_lt = *lt; + gettimeofday (&tv, NULL); + return memcmp (lt, &saved_lt, sizeof (struct tm)) != 0; + ]])], + [gl_cv_func_gettimeofday_clobber=no], + [gl_cv_func_gettimeofday_clobber=yes], + [# When cross-compiling: + case "$host_os" in + # Guess all is fine on glibc systems. + *-gnu* | gnu*) gl_cv_func_gettimeofday_clobber="guessing no" ;; + # Guess no on native Windows. + mingw*) gl_cv_func_gettimeofday_clobber="guessing no" ;; + # If we don't know, assume the worst. + *) gl_cv_func_gettimeofday_clobber="guessing yes" ;; + esac + ])]) + + case "$gl_cv_func_gettimeofday_clobber" in + *yes) + REPLACE_GETTIMEOFDAY=1 + AC_DEFINE([GETTIMEOFDAY_CLOBBERS_LOCALTIME], [1], + [Define if gettimeofday clobbers the localtime buffer.]) + gl_LOCALTIME_BUFFER_NEEDED + ;; + esac +]) + +# Prerequisites of lib/gettimeofday.c. +AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [:]) |