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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2010-08-01 01:05:53 +0200
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2010-08-01 01:05:53 +0200
commit68567b88ee8f9e395e0c1f0a565affe8a1d4d68b (patch)
tree07d3b7b96832493cb3cc57a26e88157e354cf899 /libpthread/sysdeps/generic/sem-post.c
parentfa0f7d1afb65bf077edfcc0f8977f95fca5656b9 (diff)
Move files to libpthread/ for inclusion along hurd
Diffstat (limited to 'libpthread/sysdeps/generic/sem-post.c')
-rw-r--r--libpthread/sysdeps/generic/sem-post.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/libpthread/sysdeps/generic/sem-post.c b/libpthread/sysdeps/generic/sem-post.c
new file mode 100644
index 00000000..6d438bf2
--- /dev/null
+++ b/libpthread/sysdeps/generic/sem-post.c
@@ -0,0 +1,62 @@
+/* Post a semaphore. Generic version.
+ Copyright (C) 2005, 2006 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <semaphore.h>
+#include <assert.h>
+
+#include <pt-internal.h>
+
+int
+__sem_post (sem_t *sem)
+{
+ struct __pthread *wakeup;
+
+ __pthread_spin_lock (&sem->__lock);
+ if (sem->__value > 0)
+ /* Do a quick up. */
+ {
+ assert (! sem->__queue);
+ sem->__value ++;
+ __pthread_spin_unlock (&sem->__lock);
+ return 0;
+ }
+
+ if (! sem->__queue)
+ /* No one waiting. */
+ {
+ sem->__value = 1;
+ __pthread_spin_unlock (&sem->__lock);
+ return 0;
+ }
+
+ /* Wake someone up. */
+
+ /* First dequeue someone. */
+ wakeup = sem->__queue;
+ __pthread_dequeue (wakeup);
+
+ /* Then drop the lock and transfer control. */
+ __pthread_spin_unlock (&sem->__lock);
+
+ __pthread_wakeup (wakeup);
+
+ return 0;
+}
+
+strong_alias (__sem_post, sem_post);