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emacs/m4/timer_time.m4
2023-01-07 15:32:56 -08:00

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# timer_time.m4 serial 6
dnl Copyright (C) 2011-2023 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.
# Check for timer_settime, and set TIMER_TIME_LIB.
AC_DEFUN([gl_TIMER_TIME],
[
dnl Based on clock_time.m4. See details there.
AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
dnl Test whether the gnulib module 'threadlib' is in use.
dnl Some packages like Emacs use --avoid=threadlib.
dnl Write the symbol in such a way that it does not cause 'aclocal' to pick
dnl the threadlib.m4 file that is installed in $PREFIX/share/aclocal/.
m4_ifdef([gl_][PTHREADLIB], [AC_REQUIRE([gl_][PTHREADLIB])])
AC_CHECK_DECL([timer_settime], [], [],
[[#include <time.h>
]])
TIMER_TIME_LIB=
AC_SUBST([TIMER_TIME_LIB])
AS_IF([test "$ac_cv_have_decl_timer_settime" = yes], [
gl_saved_libs=$LIBS
AC_SEARCH_LIBS([timer_settime], [rt posix4],
[test "$ac_cv_search_timer_settime" = "none required" ||
TIMER_TIME_LIB=$ac_cv_search_timer_settime])
m4_ifdef([gl_][PTHREADLIB],
[dnl GLIBC uses threads to emulate posix timers when kernel support
dnl is not available (like Linux < 2.6 or when used with kFreeBSD)
dnl Now the pthread lib is linked automatically in the normal case,
dnl but when linking statically, it needs to be explicitly specified.
AC_EGREP_CPP([Thread],
[#include <features.h>
#ifdef __GNU_LIBRARY__
#if ((__GLIBC__ == 2 && __GLIBC_MINOR__ >= 2) || (__GLIBC__ > 2)) \
&& !(__UCLIBC__ && __HAS_NO_THREADS__)
Thread emulation available
#endif
#endif
],
[TIMER_TIME_LIB="$TIMER_TIME_LIB $LIBPMULTITHREAD"])])
AC_CHECK_FUNCS([timer_settime])
LIBS=$gl_saved_libs
])
dnl For backward compatibility.
LIB_TIMER_TIME="$TIMER_TIME_LIB"
AC_SUBST([LIB_TIMER_TIME])
])