From ea562ee977d4b48500a9b117e543e9c4ae0eb05e Mon Sep 17 00:00:00 2001
From: Joel Sherrill <joel.sherrill@OARcorp.com>
Date: Thu, 12 Aug 1999 18:22:17 +0000
Subject: Patch from Ralf Corsepius <corsepiu@faw.uni-ulm.de>:

    After upgrading my linux box to the brand new SuSE 6.2 release, which is
    glibc-2.1 based, I came across a bug in RTEMS - IIRC, I even warned you
    about it about 1/2 a year ago, but nothing has been done since then :-.

    The *.m4 macros to check for SYSV/IPC are broken for linux/glibc2.1,
    because they assume that linux always defines union semun, which isn't
    true anymore for glibc2.1 (the manpage for semctl states _X_OPEN
    specifies it this way). Therefore I have tried to implement a more
    general approach for handling SYSV for unix/posix which checks for
    presence of struct semun, instead of trying  to evaluate OS specific
    preprocessor symbols.

    This approach is a bit adventureous, because I only tested it with
    linux/glibc2.1 and linux/libc5, but not under other Unix variants RTEMS
    supports. I am quite confident it will work on other hosts, too, but who
    knows :-.

    [FYI: I think this might also is the cause of some problems with RedHat
    6.X / Mandrake linux recently reported on the rtems list -- rtems-4.0.0
    can not be build for posix on any glibc2.1 based host]

    Furthermore the patch below contains a couple of minor fixes and
    configuration cleanups, which IMO should be applied before releasing a
    new snapshot.

    To apply this patch:

        cd <source-tree>
        patch -p1 < rtems-rc-19990709-8.diff
        ./autogen
---
 aclocal/sysv-ipc.m4 | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

(limited to 'aclocal/sysv-ipc.m4')

diff --git a/aclocal/sysv-ipc.m4 b/aclocal/sysv-ipc.m4
index 59a5f5b50c..883921e2c8 100644
--- a/aclocal/sysv-ipc.m4
+++ b/aclocal/sysv-ipc.m4
@@ -16,26 +16,44 @@ dnl All of the calls use IPC_PRIVATE, so tests will not unintentionally
 dnl modify any existing key sets.  See the man pages for semget, shmget, 
 dnl msgget, semctl, shmctl and msgctl for details.
 
+AC_DEFUN(RTEMS_UNION_SEMUN,
+[
+AC_CACHE_CHECK([whether $RTEMS_HOST defines union semun],
+  rtems_cv_HAS_UNION_SEMUN,
+  [AC_TRY_COMPILE([
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/sem.h>],
+[union semun arg ;],
+[rtems_cv_HAS_UNION_SEMUN="yes"],
+[rtems_cv_HAS_UNION_SEMUN="no"])
+
+if test "$rtems_cv_HAS_UNION_SEMUN" = "yes"; then
+    AC_DEFINE(HAS_UNION_SEMUN)
+fi])
+])
+
 AC_DEFUN(RTEMS_SYSV_SEM,
 [AC_REQUIRE([AC_PROG_CC]) 
 AC_REQUIRE([RTEMS_CANONICAL_HOST])
 AC_CACHE_CHECK(whether $RTEMS_HOST supports System V semaphores,
 rtems_cv_sysv_sem,
 [
-AC_TRY_RUN([
+AC_TRY_RUN(
+[
 #include <sys/types.h>
 #include <sys/ipc.h>
 #include <sys/sem.h>
-int main () {
-#if !defined(sun) 
-  union semun arg ;
-#else
+#if !HAS_UNION_SEMUN
   union semun {
     int val;
     struct semid_ds *buf;
     ushort *array;
-  } arg;
+  } ;
 #endif
+int main () {
+  union semun arg ;
+
   int id=semget(IPC_PRIVATE,1,IPC_CREAT|0400);
   if (id == -1)
     exit(1);
@@ -98,6 +116,7 @@ rtems_cv_sysv_msg="yes", rtems_cv_sysv_msg="no", :)
 AC_DEFUN(RTEMS_CHECK_SYSV_UNIX,
 [AC_REQUIRE([RTEMS_CANONICAL_HOST])
 if test "$RTEMS_CPU" = "unix" ; then
+  RTEMS_UNION_SEMUN
   RTEMS_SYSV_SEM
   if test "$rtems_cv_sysv_sem" != "yes" ; then
     AC_MSG_ERROR([System V semaphores don't work, required by simulator])
-- 
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