m4/librt_timers.m4

   1 # HW_HEADER_TIME_H
   2 # ------------------
   3 # Define HAVE_TIME_H to 1 if <time.h> is available.
   4 AC_DEFUN([HW_HEADER_TIME_H],
   5 [
   6   AC_PREREQ([2.60])dnl Older releases should work if AC_CHECK_HEADERS is used.
   7   AC_CHECK_HEADERS_ONCE([time.h])
   8 ])# HW_HEADER_TIME_H
   9
  10 # HW_LIBRT_TIMERS
  11 # -----------------
  12 # Set $hw_cv_librt_timers and $hw_cv_librt_timers_posix to "yes" or "no",
  13 # respectively.  If the timer_create() function is available and
  14 # POSIX compliant, then the system's timer_create(), timer_settime(),
  15 # and timer_delete() functions are used. Otherwise, make sure
  16 # the replacement functions will be built.
  17 #
  18 # In the case where we are cross compiling, the POSIX detection of
  19 # the timer_create() function is skipped, and instead the usual check
  20 # for the existence of all the timer_* functions is done using
  21 # AC_REPLACE_FUNCS.
  22 #
  23 # If enable_timer_replacement=true, the replacements is forced to be built.
  24 AC_DEFUN([HW_LIBRT_TIMERS],
  25 [
  26   AC_PREREQ([2.60])dnl 2.59 should work if some AC_TYPE_* macros are replaced.
  27   AC_REQUIRE([HW_HEADER_TIME_H])dnl Our check evaluates HAVE_TIME_H.
  28
  29   if test "xtrue" != x"$enable_timer_replacement"; then
  30           AC_CHECK_FUNC([timer_create],
  31                 [hw_cv_librt_timers=yes],
  32                 [hw_cv_librt_timers=no])
  33           AS_IF([test "$hw_cv_librt_timers" = yes],
  34                 [AC_CACHE_CHECK([if timer_create is supported on the system],
  35                   [hw_cv_librt_timers_posix],
  36                   [AC_RUN_IFELSE(
  37                         [AC_LANG_PROGRAM(
  38                           [[#if HAVE_TIME_H
  39                           #include <time.h>
  40                           #endif
  41               #include <errno.h>
  42                           static int test_timer_create()
  43                           {
  44                 timer_t timerid;
  45                 if(timer_create(CLOCK_REALTIME, NULL, &timerid) != 0)
  46                 {
  47                     /*
  48                       On this system, although the function is available,
  49                       no meaningful implementation is provided.
  50                     */
  51                     if(errno == ENOSYS)
  52                     {
  53                         return 1;
  54                     }
  55                 }
  56                 return 0;
  57                           }]],
  58                           [[return test_timer_create();]])],
  59                         [hw_cv_librt_timers_posix=yes],
  60                         [hw_cv_librt_timers_posix=no],
  61                         [hw_cv_librt_timers_posix=autodetect])])],
  62                 [hw_cv_librt_timers_posix=no])
  63   else
  64       hw_cv_librt_timers_posix=no
  65   fi
  66
  67   # If the system does not have a POSIX timer_create(), then use
  68   # Check's reimplementation of the timer_* calls
  69   AS_IF([test "$hw_cv_librt_timers_posix" = no],
  70     [_HW_LIBRT_TIMERS_REPLACE])
  71
  72   # If we are cross compiling, do the normal check for the
  73   # timer_* calls.
  74   AS_IF([test "$hw_cv_librt_timers_posix" = autodetect],
  75     [AC_REPLACE_FUNCS([timer_create timer_settime timer_delete])
  76      AC_CHECK_DECLS([timer_create, timer_settime, timer_delete])])
  77 ])# HW_LIBRT_TIMERS
  78
  79 # _HW_LIBRT_TIMERS_REPLACE
  80 # ------------------------
  81 # Arrange for building timer_create.c, timer_settime.c, and
  82 # timer_delete.c.
  83 AC_DEFUN([_HW_LIBRT_TIMERS_REPLACE],
  84 [
  85   AS_IF([test "x$_hw_cv_librt_timers_replace_done" != xyes],
  86     [AC_LIBOBJ([timer_create])
  87      AC_LIBOBJ([timer_settime])
  88      AC_LIBOBJ([timer_delete])
  89     _hw_cv_librt_timers_replace_done=yes])
  90 ])# _HW_LIBRT_TIMERS_REPLACE