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<h1>apr_shm.h</h1><a href="apr__shm_8h.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/* Copyright 2000-2004 The Apache Software Foundation</span>
00002 <span class="comment"> *</span>
00003 <span class="comment"> * Licensed under the Apache License, Version 2.0 (the "License");</span>
00004 <span class="comment"> * you may not use this file except in compliance with the License.</span>
00005 <span class="comment"> * You may obtain a copy of the License at</span>
00006 <span class="comment"> *</span>
00007 <span class="comment"> * http://www.apache.org/licenses/LICENSE-2.0</span>
00008 <span class="comment"> *</span>
00009 <span class="comment"> * Unless required by applicable law or agreed to in writing, software</span>
00010 <span class="comment"> * distributed under the License is distributed on an "AS IS" BASIS,</span>
00011 <span class="comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
00012 <span class="comment"> * See the License for the specific language governing permissions and</span>
00013 <span class="comment"> * limitations under the License.</span>
00014 <span class="comment"> */</span>
00015
00016 <span class="preprocessor">#ifndef APR_SHM_H</span>
00017 <span class="preprocessor"></span><span class="preprocessor">#define APR_SHM_H</span>
00018 <span class="preprocessor"></span><span class="comment"></span>
00019 <span class="comment">/**</span>
00020 <span class="comment"> * @file apr_shm.h</span>
00021 <span class="comment"> * @brief APR Shared Memory Routines</span>
00022 <span class="comment"> */</span>
00023
00024 <span class="preprocessor">#include "<a class="code" href="apr_8h.html">apr.h</a>"</span>
00025 <span class="preprocessor">#include "<a class="code" href="apr__pools_8h.html">apr_pools.h</a>"</span>
00026 <span class="preprocessor">#include "<a class="code" href="apr__errno_8h.html">apr_errno.h</a>"</span>
00027
00028 <span class="preprocessor">#ifdef __cplusplus</span>
00029 <span class="preprocessor"></span><span class="keyword">extern</span> <span class="stringliteral">"C"</span> {
00030 <span class="preprocessor">#endif </span><span class="comment">/* __cplusplus */</span>
00031 <span class="comment"></span>
00032 <span class="comment">/**</span>
00033 <span class="comment"> * @defgroup apr_shm Shared Memory Routines</span>
00034 <span class="comment"> * @ingroup APR </span>
00035 <span class="comment"> * @{</span>
00036 <span class="comment"> */</span>
00037 <span class="comment"></span>
00038 <span class="comment">/**</span>
00039 <span class="comment"> * Private, platform-specific data struture representing a shared memory</span>
00040 <span class="comment"> * segment.</span>
00041 <span class="comment"> */</span>
<a name="l00042"></a><a class="code" href="group__apr__shm.html#ga0">00042</a> <span class="keyword">typedef</span> <span class="keyword">struct </span><a class="code" href="group__apr__shm.html#ga0">apr_shm_t</a> <a class="code" href="group__apr__shm.html#ga0">apr_shm_t</a>;
00043 <span class="comment"></span>
00044 <span class="comment">/**</span>
00045 <span class="comment"> * Create and make accessable a shared memory segment.</span>
00046 <span class="comment"> * @param m The shared memory structure to create.</span>
00047 <span class="comment"> * @param reqsize The desired size of the segment.</span>
00048 <span class="comment"> * @param filename The file to use for shared memory on platforms that</span>
00049 <span class="comment"> * require it.</span>
00050 <span class="comment"> * @param pool the pool from which to allocate the shared memory</span>
00051 <span class="comment"> * structure.</span>
00052 <span class="comment"> * @remark A note about Anonymous vs. Named shared memory segments:</span>
00053 <span class="comment"> * Not all plaforms support anonymous shared memory segments, but in</span>
00054 <span class="comment"> * some cases it is prefered over other types of shared memory</span>
00055 <span class="comment"> * implementations. Passing a NULL 'file' parameter to this function</span>
00056 <span class="comment"> * will cause the subsystem to use anonymous shared memory segments.</span>
00057 <span class="comment"> * If such a system is not available, APR_ENOTIMPL is returned.</span>
00058 <span class="comment"> * @remark A note about allocation sizes:</span>
00059 <span class="comment"> * On some platforms it is necessary to store some metainformation</span>
00060 <span class="comment"> * about the segment within the actual segment. In order to supply</span>
00061 <span class="comment"> * the caller with the requested size it may be necessary for the</span>
00062 <span class="comment"> * implementation to request a slightly greater segment length</span>
00063 <span class="comment"> * from the subsystem. In all cases, the apr_shm_baseaddr_get()</span>
00064 <span class="comment"> * function will return the first usable byte of memory.</span>
00065 <span class="comment"> * </span>
00066 <span class="comment"> */</span>
00067 <a class="code" href="group__apr__platform.html#ga123">APR_DECLARE</a>(apr_status_t) apr_shm_create(apr_shm_t **m,
00068 apr_size_t reqsize,
00069 const <span class="keywordtype">char</span> *filename,
00070 apr_pool_t *pool);
00071 <span class="comment"></span>
00072 <span class="comment">/**</span>
00073 <span class="comment"> * Remove shared memory segment associated with a filename.</span>
00074 <span class="comment"> * @param filename The filename associated with shared-memory segment which</span>
00075 <span class="comment"> * needs to be removed</span>
00076 <span class="comment"> * @param pool The pool used for file operations</span>
00077 <span class="comment"> * @remark This function is only supported on platforms which support</span>
00078 <span class="comment"> * name-based shared memory segments, and will return APR_ENOTIMPL on</span>
00079 <span class="comment"> * platforms without such support.</span>
00080 <span class="comment"> */</span>
00081 APR_DECLARE(apr_status_t) apr_shm_remove(const <span class="keywordtype">char</span> *filename,
00082 apr_pool_t *pool);
00083 <span class="comment"></span>
00084 <span class="comment">/**</span>
00085 <span class="comment"> * Destroy a shared memory segment and associated memory.</span>
00086 <span class="comment"> * @param m The shared memory segment structure to destroy.</span>
00087 <span class="comment"> */</span>
00088 APR_DECLARE(apr_status_t) apr_shm_destroy(apr_shm_t *m);
00089 <span class="comment"></span>
00090 <span class="comment">/**</span>
00091 <span class="comment"> * Attach to a shared memory segment that was created</span>
00092 <span class="comment"> * by another process.</span>
00093 <span class="comment"> * @param m The shared memory structure to create.</span>
00094 <span class="comment"> * @param filename The file used to create the original segment.</span>
00095 <span class="comment"> * (This MUST match the original filename.)</span>
00096 <span class="comment"> * @param pool the pool from which to allocate the shared memory</span>
00097 <span class="comment"> * structure for this process.</span>
00098 <span class="comment"> */</span>
00099 APR_DECLARE(apr_status_t) apr_shm_attach(apr_shm_t **m,
00100 const <span class="keywordtype">char</span> *filename,
00101 apr_pool_t *pool);
00102 <span class="comment"></span>
00103 <span class="comment">/**</span>
00104 <span class="comment"> * Detach from a shared memory segment without destroying it.</span>
00105 <span class="comment"> * @param m The shared memory structure representing the segment</span>
00106 <span class="comment"> * to detach from.</span>
00107 <span class="comment"> */</span>
00108 APR_DECLARE(apr_status_t) apr_shm_detach(apr_shm_t *m);
00109 <span class="comment"></span>
00110 <span class="comment">/**</span>
00111 <span class="comment"> * Retrieve the base address of the shared memory segment.</span>
00112 <span class="comment"> * NOTE: This address is only usable within the callers address</span>
00113 <span class="comment"> * space, since this API does not guarantee that other attaching</span>
00114 <span class="comment"> * processes will maintain the same address mapping.</span>
00115 <span class="comment"> * @param m The shared memory segment from which to retrieve</span>
00116 <span class="comment"> * the base address.</span>
00117 <span class="comment"> * @return address, aligned by APR_ALIGN_DEFAULT.</span>
00118 <span class="comment"> */</span>
00119 APR_DECLARE(<span class="keywordtype">void</span> *) apr_shm_baseaddr_get(const apr_shm_t *m);
00120 <span class="comment"></span>
00121 <span class="comment">/**</span>
00122 <span class="comment"> * Retrieve the length of a shared memory segment in bytes.</span>
00123 <span class="comment"> * @param m The shared memory segment from which to retrieve</span>
00124 <span class="comment"> * the segment length.</span>
00125 <span class="comment"> */</span>
00126 APR_DECLARE(apr_size_t) apr_shm_size_get(const apr_shm_t *m);
00127 <span class="comment"></span>
00128 <span class="comment">/**</span>
00129 <span class="comment"> * Get the pool used by this shared memory segment.</span>
00130 <span class="comment"> */</span>
00131 APR_POOL_DECLARE_ACCESSOR(shm);
00132 <span class="comment"></span>
00133 <span class="comment">/** @} */</span>
00134
00135 #ifdef __cplusplus
00136 }
00137 #endif
00138
00139 #endif <span class="comment">/* APR_SHM_T */</span>
</pre></div><hr size="1"><address style="align: right;"><small>Generated on Sun Mar 20 19:52:26 2005 for Apache Portable Runtime by
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