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100 lines
3.3 KiB
Plaintext
100 lines
3.3 KiB
Plaintext
dnl Reentrant time functions: localtime_r, gmtime_r.
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dnl Copyright (C) 2003, 2006-2023 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl Written by Paul Eggert.
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AC_DEFUN([gl_TIME_R],
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[
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dnl Persuade glibc and Solaris <time.h> to declare localtime_r.
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AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
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AC_REQUIRE([gl_TIME_H_DEFAULTS])
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AC_REQUIRE([AC_C_RESTRICT])
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dnl Some systems don't declare localtime_r() and gmtime_r() if _REENTRANT is
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dnl not defined.
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AC_CHECK_DECLS([localtime_r], [], [],
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[[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
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gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
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been included before. */
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#if defined __MINGW32__
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# include <unistd.h>
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#endif
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#include <time.h>
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]])
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if test $ac_cv_have_decl_localtime_r = no; then
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HAVE_DECL_LOCALTIME_R=0
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fi
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AC_CHECK_FUNCS_ONCE([localtime_r])
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if test $ac_cv_func_localtime_r = yes; then
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HAVE_LOCALTIME_R=1
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AC_CACHE_CHECK([whether localtime_r is compatible with its POSIX signature],
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[gl_cv_time_r_posix],
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[AC_COMPILE_IFELSE(
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[AC_LANG_PROGRAM(
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[[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
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gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
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been included before. */
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#if defined __MINGW32__
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# include <unistd.h>
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#endif
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#include <time.h>
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]],
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[[/* We don't need to append 'restrict's to the argument types,
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even though the POSIX signature has the 'restrict's,
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since C99 says they can't affect type compatibility. */
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struct tm * (*ptr) (time_t const *, struct tm *) = localtime_r;
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if (ptr) return 0;
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/* Check the return type is a pointer.
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On HP-UX 10 it is 'int'. */
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*localtime_r (0, 0);]])
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],
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[gl_cv_time_r_posix=yes],
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[gl_cv_time_r_posix=no])
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])
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if test $gl_cv_time_r_posix = yes; then
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REPLACE_LOCALTIME_R=0
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else
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REPLACE_LOCALTIME_R=1
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fi
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else
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HAVE_LOCALTIME_R=0
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dnl On mingw, localtime_r() is defined as an inline function; use through a
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dnl direct function call works but the use as a function pointer leads to a
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dnl link error.
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AC_CACHE_CHECK([whether localtime_r exists as an inline function],
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[gl_cv_func_localtime_r_inline],
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[AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[/* mingw's <time.h> provides the functions asctime_r, ctime_r,
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gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has
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been included before. */
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#if defined __MINGW32__
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# include <unistd.h>
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#endif
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#include <time.h>
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]],
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[[time_t a;
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struct tm r;
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localtime_r (&a, &r);
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]])
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],
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[gl_cv_func_localtime_r_inline=yes],
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[gl_cv_func_localtime_r_inline=no])
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])
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if test $gl_cv_func_localtime_r_inline = yes; then
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REPLACE_LOCALTIME_R=1
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fi
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fi
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])
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# Prerequisites of lib/time_r.c.
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AC_DEFUN([gl_PREREQ_TIME_R], [
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:
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])
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