freebsd-dev/contrib/apr/include/apr_atomic.h
Peter Wemm 937a200089 Introduce svnlite so that we can check out our source code again.
This is actually a fully functional build except:
* All internal shared libraries are static linked to make sure there
  is no interference with ports (and to reduce build time).
* It does not have the python/perl/etc plugin or API support.
* By default, it installs as "svnlite" rather than "svn".
* If WITH_SVN added in make.conf, you get "svn".
* If WITHOUT_SVNLITE is in make.conf, this is completely disabled.

To be absolutely clear, this is not intended for any use other than
checking out freebsd source and committing, like we once did with cvs.

It should be usable for small scale local repositories that don't
need the python/perl plugin architecture.
2013-06-18 02:53:45 +00:00

141 lines
4.0 KiB
C

/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef APR_ATOMIC_H
#define APR_ATOMIC_H
/**
* @file apr_atomic.h
* @brief APR Atomic Operations
*/
#include "apr.h"
#include "apr_pools.h"
#ifdef __cplusplus
extern "C" {
#endif
/**
* @defgroup apr_atomic Atomic Operations
* @ingroup APR
* @{
*/
/**
* this function is required on some platforms to initialize the
* atomic operation's internal structures
* @param p pool
* @return APR_SUCCESS on successful completion
* @remark Programs do NOT need to call this directly. APR will call this
* automatically from apr_initialize.
* @internal
*/
APR_DECLARE(apr_status_t) apr_atomic_init(apr_pool_t *p);
/*
* Atomic operations on 32-bit values
* Note: Each of these functions internally implements a memory barrier
* on platforms that require it
*/
/**
* atomically read an apr_uint32_t from memory
* @param mem the pointer
*/
APR_DECLARE(apr_uint32_t) apr_atomic_read32(volatile apr_uint32_t *mem);
/**
* atomically set an apr_uint32_t in memory
* @param mem pointer to the object
* @param val value that the object will assume
*/
APR_DECLARE(void) apr_atomic_set32(volatile apr_uint32_t *mem, apr_uint32_t val);
/**
* atomically add 'val' to an apr_uint32_t
* @param mem pointer to the object
* @param val amount to add
* @return old value pointed to by mem
*/
APR_DECLARE(apr_uint32_t) apr_atomic_add32(volatile apr_uint32_t *mem, apr_uint32_t val);
/**
* atomically subtract 'val' from an apr_uint32_t
* @param mem pointer to the object
* @param val amount to subtract
*/
APR_DECLARE(void) apr_atomic_sub32(volatile apr_uint32_t *mem, apr_uint32_t val);
/**
* atomically increment an apr_uint32_t by 1
* @param mem pointer to the object
* @return old value pointed to by mem
*/
APR_DECLARE(apr_uint32_t) apr_atomic_inc32(volatile apr_uint32_t *mem);
/**
* atomically decrement an apr_uint32_t by 1
* @param mem pointer to the atomic value
* @return zero if the value becomes zero on decrement, otherwise non-zero
*/
APR_DECLARE(int) apr_atomic_dec32(volatile apr_uint32_t *mem);
/**
* compare an apr_uint32_t's value with 'cmp'.
* If they are the same swap the value with 'with'
* @param mem pointer to the value
* @param with what to swap it with
* @param cmp the value to compare it to
* @return the old value of *mem
*/
APR_DECLARE(apr_uint32_t) apr_atomic_cas32(volatile apr_uint32_t *mem, apr_uint32_t with,
apr_uint32_t cmp);
/**
* exchange an apr_uint32_t's value with 'val'.
* @param mem pointer to the value
* @param val what to swap it with
* @return the old value of *mem
*/
APR_DECLARE(apr_uint32_t) apr_atomic_xchg32(volatile apr_uint32_t *mem, apr_uint32_t val);
/**
* compare the pointer's value with cmp.
* If they are the same swap the value with 'with'
* @param mem pointer to the pointer
* @param with what to swap it with
* @param cmp the value to compare it to
* @return the old value of the pointer
*/
APR_DECLARE(void*) apr_atomic_casptr(volatile void **mem, void *with, const void *cmp);
/**
* exchange a pair of pointer values
* @param mem pointer to the pointer
* @param with what to swap it with
* @return the old value of the pointer
*/
APR_DECLARE(void*) apr_atomic_xchgptr(volatile void **mem, void *with);
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* !APR_ATOMIC_H */