docs/manual/mod/mod_slotmem_shm.xml

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<modulesynopsis metafile="mod_slotmem_shm.xml.meta">

<name>mod_slotmem_shm</name>
<description>Slot-based shared memory provider.</description>
<status>Extension</status>
<sourcefile>mod_slotmem_shm.c</sourcefile>
<identifier>slotmem_shm_module</identifier>

<summary>
    <p><code>mod_slotmem_shm</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
    <directive module="core">DefaultRuntimeDir</directive> directive.
    </p>

    <p><code>mod_slotmem_shm</code> provides the following API functions:
    </p>

    <dl>
      <dt>apr_status_t doall(ap_slotmem_instance_t *s, ap_slotmem_callback_fn_t *func, void *data, apr_pool_t *pool)</dt>
      <dd>call the callback on all worker slots</dd>

      <dt>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)</dt>
      <dd>create a new slotmem with each item size is item_size. <code>name</code> is used to generate a filename for the persistent store of
      the shared memory if configured. Values are:
       <dl>
         <dt><code>"none"</code></dt>
         <dd><code>Anonymous shared memory and no persistent store</code></dd>
         <dt><code>"file-name"</code></dt>
         <dd><code>[DefaultRuntimeDir]/file-name</code></dd>
         <dt><code>"/absolute-file-name"</code></dt>
         <dd><code>Absolute file name</code></dd>
       </dl></dd>

      <dt>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)</dt>
      <dd>attach to an existing slotmem. See <code>create</code> for description of <code>name</code> parameter.</dd>

      <dt>apr_status_t dptr(ap_slotmem_instance_t *s, unsigned int item_id, void**mem)</dt>
      <dd>get the direct pointer to the memory associated with this worker slot.</dd>

      <dt>apr_status_t get(ap_slotmem_instance_t *s, unsigned int item_id, unsigned char *dest, apr_size_t dest_len)</dt>
      <dd>get/read the memory from this slot to dest</dd>

      <dt>apr_status_t put(ap_slotmem_instance_t *slot, unsigned int item_id, unsigned char *src, apr_size_t src_len)</dt>
      <dd>put/write the data from src to this slot</dd>

      <dt>unsigned int num_slots(ap_slotmem_instance_t *s)</dt>
      <dd>return the total number of slots in the segment</dd>

      <dt>apr_size_t slot_size(ap_slotmem_instance_t *s)</dt>
      <dd>return the total data size, in bytes, of a slot in the segment</dd>

      <dt>apr_status_t grab(ap_slotmem_instance_t *s, unsigned int *item_id);</dt>
      <dd>grab or allocate the first free slot and mark as in-use (does not do any data copying)</dd>

      <dt>apr_status_t fgrab(ap_slotmem_instance_t *s, unsigned int item_id);</dt>
      <dd>forced grab or allocate the specified slot and mark as in-use (does not do any data copying)</dd>

      <dt>apr_status_t release(ap_slotmem_instance_t *s, unsigned int item_id);</dt>
      <dd>release or free a slot and mark as not in-use (does not do any data copying)</dd>
    </dl>

</summary>

</modulesynopsis>