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48 lines
1.6 KiB
C
48 lines
1.6 KiB
C
/* sem_post -- post to a POSIX semaphore. Generic futex-using version.
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Copyright (C) 2003 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <errno.h>
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#include <sysdep.h>
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#include <lowlevellock.h>
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#include <internaltypes.h>
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#include <semaphore.h>
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#include <shlib-compat.h>
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int
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__new_sem_post (sem_t *sem)
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{
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int *futex = (int *) sem;
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int err, nr;
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__asm __volatile (__lll_rel_instr ::: "memory");
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nr = atomic_exchange_and_add (futex, 1);
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err = lll_futex_wake (futex, nr);
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if (err == 0)
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return 0;
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__set_errno (-err);
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return -1;
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}
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versioned_symbol (libpthread, __new_sem_post, sem_post, GLIBC_2_1);
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#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_1)
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strong_alias (__new_sem_post, __old_sem_post)
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compat_symbol (libpthread, __old_sem_post, sem_post, GLIBC_2_0);
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#endif
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