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<div class="title">Shared Memory Routines<div class="ingroups"><a class="el" href="group___a_p_r.html">Apache Portability Runtime library</a></div></div> </div>
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Macros</h2></td></tr>
<tr class="memitem:ga47cc28ddc5f32cf904383b9e4f82825b"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga47cc28ddc5f32cf904383b9e4f82825b">APR_SHM_NS_LOCAL</a></td></tr>
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<tr class="memitem:ga0de8e4acab42e7ff8e35e5ac9620f667"><td class="memItemLeft" align="right" valign="top">#define </td><td class="memItemRight" valign="bottom"><b>APR_SHM_NS_GLOBAL</b></td></tr>
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Typedefs</h2></td></tr>
<tr class="memitem:ga79e8c16bdeaf7ade4ef0f935249e7c2f"><td class="memItemLeft" align="right" valign="top">typedef struct <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a></td></tr>
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<tr class="heading"><td colspan="2"><h2 class="groupheader"><a name="func-members"></a>
Functions</h2></td></tr>
<tr class="memitem:gac370c4943c22505ce2b0d57c51805480"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#gac370c4943c22505ce2b0d57c51805480">apr_shm_create</a> (<a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> **m, apr_size_t reqsize, const char *filename, <a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> *pool)</td></tr>
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<tr class="memitem:ga21baaa66956641e06e072501f61882e7"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga21baaa66956641e06e072501f61882e7">apr_shm_create_ex</a> (<a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> **m, apr_size_t reqsize, const char *filename, <a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> *pool, apr_int32_t flags)</td></tr>
<tr class="separator:ga21baaa66956641e06e072501f61882e7"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gaee8b7d9b952ff6157ddbb00fabb477e0"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#gaee8b7d9b952ff6157ddbb00fabb477e0">apr_shm_remove</a> (const char *filename, <a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> *pool)</td></tr>
<tr class="separator:gaee8b7d9b952ff6157ddbb00fabb477e0"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga7de5b65a9c7d9840bfa289854f8d59d4"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga7de5b65a9c7d9840bfa289854f8d59d4">apr_shm_destroy</a> (<a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> *m)</td></tr>
<tr class="separator:ga7de5b65a9c7d9840bfa289854f8d59d4"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga0e542941c280cb72b78e30d452464759"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga0e542941c280cb72b78e30d452464759">apr_shm_attach</a> (<a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> **m, const char *filename, <a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> *pool)</td></tr>
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<tr class="memitem:ga088260723c96815610ff628f358d3630"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga088260723c96815610ff628f358d3630">apr_shm_attach_ex</a> (<a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> **m, const char *filename, <a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> *pool, apr_int32_t flags)</td></tr>
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<tr class="memitem:ga900095a06d3fdb4cdd04ca4449a9d42a"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga900095a06d3fdb4cdd04ca4449a9d42a">apr_shm_detach</a> (<a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> *m)</td></tr>
<tr class="separator:ga900095a06d3fdb4cdd04ca4449a9d42a"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:gade739e1f5f4e88c93256a63ebfd47d4d"><td class="memItemLeft" align="right" valign="top">void * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#gade739e1f5f4e88c93256a63ebfd47d4d">apr_shm_baseaddr_get</a> (const <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> *m)</td></tr>
<tr class="separator:gade739e1f5f4e88c93256a63ebfd47d4d"><td class="memSeparator" colspan="2"> </td></tr>
<tr class="memitem:ga557ae85d3f225620a77ad80caeaacac7"><td class="memItemLeft" align="right" valign="top">apr_size_t </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga557ae85d3f225620a77ad80caeaacac7">apr_shm_size_get</a> (const <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> *m)</td></tr>
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<tr class="memitem:ga072c40df7643e697885935ae65545098"><td class="memItemLeft" align="right" valign="top"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> * </td><td class="memItemRight" valign="bottom"><a class="el" href="group__apr__shm.html#ga072c40df7643e697885935ae65545098">apr_shm_pool_get</a> (const <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> *theshm)</td></tr>
<tr class="separator:ga072c40df7643e697885935ae65545098"><td class="memSeparator" colspan="2"> </td></tr>
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<a name="details" id="details"></a><h2 class="groupheader">Detailed Description</h2>
<h2 class="groupheader">Macro Definition Documentation</h2>
<a id="ga0de8e4acab42e7ff8e35e5ac9620f667"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga0de8e4acab42e7ff8e35e5ac9620f667">◆ </a></span>APR_SHM_NS_GLOBAL</h2>
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<td class="memname">#define APR_SHM_NS_GLOBAL</td>
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<b>Value:</b><div class="fragment"><div class="line">2 <span class="comment">/* Create or attach to named shared memory</span></div><div class="line"><span class="comment"> * segment in the "Global" namespace on</span></div><div class="line"><span class="comment"> * Windows. (Ignored on other platforms.)</span></div><div class="line"><span class="comment"> */</span></div></div><!-- fragment -->
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<a id="ga47cc28ddc5f32cf904383b9e4f82825b"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga47cc28ddc5f32cf904383b9e4f82825b">◆ </a></span>APR_SHM_NS_LOCAL</h2>
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<td class="memname">#define APR_SHM_NS_LOCAL</td>
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<b>Value:</b><div class="fragment"><div class="line">1 <span class="comment">/* Create or attach to named shared memory</span></div><div class="line"><span class="comment"> * segment in the "Local" namespace on</span></div><div class="line"><span class="comment"> * Windows. (Ignored on other platforms.)</span></div><div class="line"><span class="comment"> * By default, the "Global" namespace is</span></div><div class="line"><span class="comment"> * used for privileged processes and the</span></div><div class="line"><span class="comment"> * "Local" namespace is used otherwise.</span></div><div class="line"><span class="comment"> */</span></div></div><!-- fragment --><p>Special processing flags for <a class="el" href="group__apr__shm.html#ga21baaa66956641e06e072501f61882e7">apr_shm_create_ex()</a> and <a class="el" href="group__apr__shm.html#ga088260723c96815610ff628f358d3630">apr_shm_attach_ex()</a>. </p>
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</div>
<h2 class="groupheader">Typedef Documentation</h2>
<a id="ga79e8c16bdeaf7ade4ef0f935249e7c2f"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga79e8c16bdeaf7ade4ef0f935249e7c2f">◆ </a></span>apr_shm_t</h2>
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<td class="memname">typedef struct <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a></td>
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<p>Private, platform-specific data struture representing a shared memory segment. </p>
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<h2 class="groupheader">Function Documentation</h2>
<a id="ga0e542941c280cb72b78e30d452464759"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga0e542941c280cb72b78e30d452464759">◆ </a></span>apr_shm_attach()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_attach </td>
<td>(</td>
<td class="paramtype"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> ** </td>
<td class="paramname"><em>m</em>, </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">const char * </td>
<td class="paramname"><em>filename</em>, </td>
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<tr>
<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> * </td>
<td class="paramname"><em>pool</em> </td>
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<p>Attach to a shared memory segment that was created by another process. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">m</td><td>The shared memory structure to create. </td></tr>
<tr><td class="paramname">filename</td><td>The file used to create the original segment. (This MUST match the original filename.) </td></tr>
<tr><td class="paramname">pool</td><td>the pool from which to allocate the shared memory structure for this process. </td></tr>
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</dd>
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<a id="ga088260723c96815610ff628f358d3630"></a>
<h2 class="memtitle"><span class="permalink"><a href="#ga088260723c96815610ff628f358d3630">◆ </a></span>apr_shm_attach_ex()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_attach_ex </td>
<td>(</td>
<td class="paramtype"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> ** </td>
<td class="paramname"><em>m</em>, </td>
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<td class="paramkey"></td>
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<td class="paramtype">const char * </td>
<td class="paramname"><em>filename</em>, </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> * </td>
<td class="paramname"><em>pool</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">apr_int32_t </td>
<td class="paramname"><em>flags</em> </td>
</tr>
<tr>
<td></td>
<td>)</td>
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<p>Attach to a shared memory segment that was created by another process, with platform-specific processing. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">m</td><td>The shared memory structure to create. </td></tr>
<tr><td class="paramname">filename</td><td>The file used to create the original segment. (This MUST match the original filename.) </td></tr>
<tr><td class="paramname">pool</td><td>the pool from which to allocate the shared memory structure for this process. </td></tr>
<tr><td class="paramname">flags</td><td>mask of APR_SHM_* (defined above) </td></tr>
</table>
</dd>
</dl>
</div>
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<a id="gade739e1f5f4e88c93256a63ebfd47d4d"></a>
<h2 class="memtitle"><span class="permalink"><a href="#gade739e1f5f4e88c93256a63ebfd47d4d">◆ </a></span>apr_shm_baseaddr_get()</h2>
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<td class="memname">void* apr_shm_baseaddr_get </td>
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<td class="paramtype">const <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> * </td>
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<p>Retrieve the base address of the shared memory segment. NOTE: This address is only usable within the callers address space, since this API does not guarantee that other attaching processes will maintain the same address mapping. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">m</td><td>The shared memory segment from which to retrieve the base address. </td></tr>
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<dl class="section return"><dt>Returns</dt><dd>address, aligned by APR_ALIGN_DEFAULT. </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#gac370c4943c22505ce2b0d57c51805480">◆ </a></span>apr_shm_create()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_create </td>
<td>(</td>
<td class="paramtype"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> ** </td>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">apr_size_t </td>
<td class="paramname"><em>reqsize</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype">const char * </td>
<td class="paramname"><em>filename</em>, </td>
</tr>
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<td class="paramkey"></td>
<td></td>
<td class="paramtype"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> * </td>
<td class="paramname"><em>pool</em> </td>
</tr>
<tr>
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<p>Create and make accessible a shared memory segment with default properties. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">m</td><td>The shared memory structure to create. </td></tr>
<tr><td class="paramname">reqsize</td><td>The desired size of the segment. </td></tr>
<tr><td class="paramname">filename</td><td>The file to use for shared memory on platforms that require it. </td></tr>
<tr><td class="paramname">pool</td><td>the pool from which to allocate the shared memory structure. </td></tr>
</table>
</dd>
</dl>
<dl class="section remark"><dt>Remarks</dt><dd>A note about Anonymous vs. Named shared memory segments: Not all plaforms support anonymous shared memory segments, but in some cases it is prefered over other types of shared memory implementations. Passing a NULL 'file' parameter to this function will cause the subsystem to use anonymous shared memory segments. If such a system is not available, APR_ENOTIMPL is returned. </dd>
<dd>
A note about allocation sizes: On some platforms it is necessary to store some metainformation about the segment within the actual segment. In order to supply the caller with the requested size it may be necessary for the implementation to request a slightly greater segment length from the subsystem. In all cases, the <a class="el" href="group__apr__shm.html#gade739e1f5f4e88c93256a63ebfd47d4d">apr_shm_baseaddr_get()</a> function will return the first usable byte of memory. </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga21baaa66956641e06e072501f61882e7">◆ </a></span>apr_shm_create_ex()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_create_ex </td>
<td>(</td>
<td class="paramtype"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> ** </td>
<td class="paramname"><em>m</em>, </td>
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<td class="paramtype">apr_size_t </td>
<td class="paramname"><em>reqsize</em>, </td>
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<td class="paramtype"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> * </td>
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<p>Create and make accessible a shared memory segment with platform- specific processing. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">m</td><td>The shared memory structure to create. </td></tr>
<tr><td class="paramname">reqsize</td><td>The desired size of the segment. </td></tr>
<tr><td class="paramname">filename</td><td>The file to use for shared memory on platforms that require it. </td></tr>
<tr><td class="paramname">pool</td><td>the pool from which to allocate the shared memory structure. </td></tr>
<tr><td class="paramname">flags</td><td>mask of APR_SHM_* (defined above) </td></tr>
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<dl class="section remark"><dt>Remarks</dt><dd>A note about Anonymous vs. Named shared memory segments: Not all plaforms support anonymous shared memory segments, but in some cases it is prefered over other types of shared memory implementations. Passing a NULL 'file' parameter to this function will cause the subsystem to use anonymous shared memory segments. If such a system is not available, APR_ENOTIMPL is returned. </dd>
<dd>
A note about allocation sizes: On some platforms it is necessary to store some metainformation about the segment within the actual segment. In order to supply the caller with the requested size it may be necessary for the implementation to request a slightly greater segment length from the subsystem. In all cases, the <a class="el" href="group__apr__shm.html#gade739e1f5f4e88c93256a63ebfd47d4d">apr_shm_baseaddr_get()</a> function will return the first usable byte of memory. </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga7de5b65a9c7d9840bfa289854f8d59d4">◆ </a></span>apr_shm_destroy()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_destroy </td>
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<td class="paramtype"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> * </td>
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<p>Destroy a shared memory segment and associated memory. </p><dl class="params"><dt>Parameters</dt><dd>
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<tr><td class="paramname">m</td><td>The shared memory segment structure to destroy. </td></tr>
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<h2 class="memtitle"><span class="permalink"><a href="#ga900095a06d3fdb4cdd04ca4449a9d42a">◆ </a></span>apr_shm_detach()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_detach </td>
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<td class="paramtype"><a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> * </td>
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<p>Detach from a shared memory segment without destroying it. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">m</td><td>The shared memory structure representing the segment to detach from. </td></tr>
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</dd>
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<h2 class="memtitle"><span class="permalink"><a href="#ga072c40df7643e697885935ae65545098">◆ </a></span>apr_shm_pool_get()</h2>
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<td class="memname"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a>* apr_shm_pool_get </td>
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<td class="paramtype">const <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> * </td>
<td class="paramname"><em>theshm</em></td><td>)</td>
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<p>Get the pool used by this shared memory segment. </p>
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<h2 class="memtitle"><span class="permalink"><a href="#gaee8b7d9b952ff6157ddbb00fabb477e0">◆ </a></span>apr_shm_remove()</h2>
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<td class="memname"><a class="el" href="group__apr__errno.html#gaf76ee4543247e9fb3f3546203e590a6c">apr_status_t</a> apr_shm_remove </td>
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<td class="paramtype">const char * </td>
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<td class="paramtype"><a class="el" href="group__apr__pools.html#gaf137f28edcf9a086cd6bc36c20d7cdfb">apr_pool_t</a> * </td>
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<p>Remove named resource associated with a shared memory segment, preventing attachments to the resource, but not destroying it. </p><dl class="params"><dt>Parameters</dt><dd>
<table class="params">
<tr><td class="paramname">filename</td><td>The filename associated with shared-memory segment which needs to be removed </td></tr>
<tr><td class="paramname">pool</td><td>The pool used for file operations </td></tr>
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<dl class="section remark"><dt>Remarks</dt><dd>This function is only supported on platforms which support name-based shared memory segments, and will return APR_ENOTIMPL on platforms without such support. Removing the file while the shm is in use is not entirely portable, caller may use this to enhance obscurity of the resource, but be prepared for the call to fail, and for concurrent attempts to create a resource of the same name to also fail. The pool cleanup of apr_shm_create (apr_shm_destroy) also removes the named resource. </dd></dl>
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<h2 class="memtitle"><span class="permalink"><a href="#ga557ae85d3f225620a77ad80caeaacac7">◆ </a></span>apr_shm_size_get()</h2>
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<td class="memname">apr_size_t apr_shm_size_get </td>
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<td class="paramtype">const <a class="el" href="group__apr__shm.html#ga79e8c16bdeaf7ade4ef0f935249e7c2f">apr_shm_t</a> * </td>
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<p>Retrieve the length of a shared memory segment in bytes. </p><dl class="params"><dt>Parameters</dt><dd>
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<tr><td class="paramname">m</td><td>The shared memory segment from which to retrieve the segment length. </td></tr>
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</dd>
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