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<title>mod_slotmem_shm - Apache HTTP Server Version 2.4</title>
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<div id="preamble"><h1>Apache Module mod_slotmem_shm</h1>
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<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Slot-based shared memory provider.</td></tr>
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>slotmem_shm_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_slotmem_shm.c</td></tr></table>
<h3>Summary</h3>
<p><code class="module"><a href="../mod/mod_slotmem_shm.html">mod_slotmem_shm</a></code> is a memory provider which
provides for creation and access to a shared memory segment
in which the datasets are organized in "slots."
</p>
<p>All shared memory is cleared and cleaned with each
restart, whether graceful or not. The data itself is
stored and restored within a file noted by the <code>name</code>
parameter in the <code>create</code> and <code>attach</code>
calls. If not specified with an absolute path, the file will be
created relative to the path specified by the
<code class="directive"><a href="../mod/core.html#defaultruntimedir">DefaultRuntimeDir</a></code> directive.
</p>
<p><code class="module"><a href="../mod/mod_slotmem_shm.html">mod_slotmem_shm</a></code> provides the following API functions:
</p>
<pre class="prettyprint lang-c">/* call the callback on all worker slots */
apr_status_t doall(ap_slotmem_instance_t *s, ap_slotmem_callback_fn_t *func, void *data, apr_pool_t *pool)
/* create a new slotmem with each item size is item_size. 'name' is used to generate a filename for the persistent
store of the shared memory if configured. Values are:
"none" - Anonymous shared memory and no persistent store
"file-name" - [DefaultRuntimeDir]/file-name
"/absolute-file-name" - Absolute file name */
apr_status_t create(ap_slotmem_instance_t **new, const char *name, apr_size_t item_size, unsigned int item_num, ap_slotmem_type_t type, apr_pool_t *pool)
/* attach to an existing slotmem. See 'create()' for description of 'name' parameter */
apr_status_t attach(ap_slotmem_instance_t **new, const char *name, apr_size_t *item_size, unsigned int *item_num, apr_pool_t *pool)
/* get the direct pointer to the memory associated with this worker slot */
apr_status_t dptr(ap_slotmem_instance_t *s, unsigned int item_id, void **mem)
/* get/read the memory from this slot to dest */
apr_status_t get(ap_slotmem_instance_t *s, unsigned int item_id, unsigned char *dest, apr_size_t dest_len)
/* put/write the data from src to this slot */
apr_status_t put(ap_slotmem_instance_t *slot, unsigned int item_id, unsigned char *src, apr_size_t src_len)
/* return the total number of slots in the segment */
unsigned int num_slots(ap_slotmem_instance_t *s)
/* return the total data size, in bytes, of a slot in the segment */
apr_size_t slot_size(ap_slotmem_instance_t *s)
/* grab or allocate the first free slot and mark as in-use (does not do any data copying) */
apr_status_t grab(ap_slotmem_instance_t *s, unsigned int *item_id)
/* forced grab or allocate the specified slot and mark as in-use (does not do any data copying) */
apr_status_t fgrab(ap_slotmem_instance_t *s, unsigned int item_id)
/* release or free a slot and mark as not in-use (does not do any data copying) */
apr_status_t release(ap_slotmem_instance_t *s, unsigned int item_id)</pre>
</div>
<div id="quickview"><h3 class="directives">Directives</h3>
<p>This module provides no
directives.</p>
<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mod_slotmem_shm">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mod_slotmem_shm">Report a bug</a></li></ul></div>
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