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ETR_STRUCT_SEMUN
This macro checks to see if sys/sem.h defines struct semun. Some systems do, some systems don't. Your code must be able to deal with this possibility; if HAVE_STRUCT_SEMUM isn't defined for a given system, you have to define this structure before you can call functions like semctl().
You should call ETR_SYSV_IPC before this macro, to separate the check for System V IPC headers from the check for struct semun.
Warren Young <warren@etr-usa.com>
2001-05-28
AC_DEFUN([ETR_STRUCT_SEMUN],
[
AC_CACHE_CHECK([for struct semun], ac_cv_struct_semun, [
AC_TRY_COMPILE(
[
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
],
[ struct semun s; ],
ac_cv_struct_semun=yes,
ac_cv_struct_semun=no)
])
if test x"$ac_cv_struct_semun" = "xyes"
then
AC_DEFINE(HAVE_STRUCT_SEMUN, 1,
[ Define if your system's sys/sem.h file defines struct semun ])
fi
]) dnl ETR_STRUCT_SEMUN