diff options
Diffstat (limited to 'libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c')
-rw-r--r-- | libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c b/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c new file mode 100644 index 000000000..edb97c4ba --- /dev/null +++ b/libpthread/nptl/sysdeps/unix/sysv/linux/sem_post.c @@ -0,0 +1,58 @@ +/* sem_post -- post to a POSIX semaphore. Generic futex-using version. + Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Jakub Jelinek <jakub@redhat.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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <errno.h> +#include <sysdep.h> +#include <lowlevellock.h> +#include <internaltypes.h> +#include <semaphore.h> +#include <tls.h> + +int +__new_sem_post (sem_t *sem) +{ + struct new_sem *isem = (struct new_sem *) sem; + + __typeof (isem->value) cur; + do + { + cur = isem->value; + if (isem->value == SEM_VALUE_MAX) + { + __set_errno (EOVERFLOW); + return -1; + } + } + while (atomic_compare_and_exchange_bool_acq (&isem->value, cur + 1, cur)); + + atomic_full_barrier (); + if (isem->nwaiters > 0) + { + int err = lll_futex_wake (&isem->value, 1, + isem->private ^ FUTEX_PRIVATE_FLAG); + if (__builtin_expect (err, 0) < 0) + { + __set_errno (-err); + return -1; + } + } + return 0; +} +weak_alias(__new_sem_post, sem_post) |