# clock_time.m4 serial 4
dnl Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
dnl This file is free software, distributed under the terms of the GNU
dnl General Public License.  As a special exception to the GNU General
dnl Public License, this file may be distributed as part of a program
dnl that contains a configuration script generated by Autoconf, under
dnl the same distribution terms as the rest of that program.

# Check for clock_gettime and clock_settime, and sets LIB_CLOCK_GETTIME.
AC_DEFUN([gl_CLOCK_TIME],
[
  # dnl Persuade glibc <time.h> to declare these functions.
  AC_REQUIRE([AC_GNU_SOURCE])

  # Solaris 2.5.1 needs -lposix4 to get the clock_gettime function.
  # Solaris 7 prefers the library name -lrt to the obsolescent name -lposix4.

  # Save and restore LIBS so e.g., -lrt, isn't added to it.  Otherwise, *all*
  # programs in the package would end up linked with that potentially-shared
  # library, inducing unnecessary run-time overhead.
  fetish_saved_libs=$LIBS
    AC_SEARCH_LIBS(clock_gettime, [rt posix4],
                   [test "$ac_cv_search_clock_gettime" = "none required" ||
                    LIB_CLOCK_GETTIME=$ac_cv_search_clock_gettime])
    AC_SUBST(LIB_CLOCK_GETTIME)
    AC_CHECK_FUNCS(clock_gettime clock_settime)
  LIBS=$fetish_saved_libs
])
