2.4.x/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><module>mod_slotmem_shm</module> 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><module>mod_slotmem_shm</module> provides the following API functions:
    </p>

<highlight language="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)
</highlight>

</summary>

</modulesynopsis>