1 files changed, 50 insertions, 0 deletions
diff --git a/nptl/sem_trywait.c b/nptl/sem_trywait.c
new file mode 100644
index 0000000000..94c323c18e
--- /dev/null
+++ b/nptl/sem_trywait.c
@@ -0,0 +1,50 @@
+/* sem_trywait -- wait on a semaphore.  Generic futex-using version.
+   Copyright (C) 2003-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <sysdep.h>
+#include <lowlevellock.h>
+#include <internaltypes.h>
+#include <semaphore.h>
+#include <atomic.h>
+
+#include <shlib-compat.h>
+
+
+int
+__new_sem_trywait (sem_t *sem)
+{
+  int *futex = (int *) sem;
+  int val;
+
+  if (*futex > 0)
+    {
+      val = atomic_decrement_if_positive (futex);
+      if (val > 0)
+	return 0;
+    }
+
+  __set_errno (EAGAIN);
+  return -1;
+}
+versioned_symbol (libpthread, __new_sem_trywait, sem_trywait, GLIBC_2_1);
+#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
+strong_alias (__new_sem_trywait, __old_sem_trywait)
+compat_symbol (libpthread, __old_sem_trywait, sem_trywait, GLIBC_2_0);
+#endif