Apache HTTP Server Version 2.4

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# Apache Module mod_slotmem_shm

Available Languages: en

Description: | Slot-based shared memory provider.
Status: | Extension
Module Identifier: | mod_slotmem_shm_module
Source File: | mod_slotmem_shm.c

### Summary

`mod_slotmem_shm` is a memory provider which provides for creation and access to a shared memory segment in which the datasets are organized in "slots."

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 `name` parameter in the `create` and `attach` calls.

`mod_slotmem_shm` provides the following API functions:

apr_status_t doall(ap_slotmem_instance_t *s, ap_slotmem_callback_fn_t *func, void *data, apr_pool_t *pool)
  call the callback on all worker slots
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)
  create a new slotmem with each item size is item_size. `name` is the filename for the persistent store of the shared memory. Values are:
  `"none"`
    `Does not persist shared memory in file.`
  `"file-name"`
    `$server_root/file-name`
  `"/absolute-file-name"`
    `$absolute-file-name`
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)
  attach to an existing slotmem. See `create` for description of `name` parameter.
apr_status_t dptr(ap_slotmem_instance_t *s, unsigned int item_id, void**mem)
  get the direct pointer to the memory associated with this worker slot.
apr_status_t get(ap_slotmem_instance_t *s, unsigned int item_id, unsigned char *dest, apr_size_t dest_len)
  get/read the memory from this slot to dest
apr_status_t put(ap_slotmem_instance_t *slot, unsigned int item_id, unsigned char *src, apr_size_t src_len)
  put/write the data from src to this slot
unsigned int num_slots(ap_slotmem_instance_t *s)
  return the total number of slots in the segment
apr_size_t slot_size(ap_slotmem_instance_t *s)
  return the total data size, in bytes, of a slot in the segment
apr_status_t grab(ap_slotmem_instance_t *s, unsigned int item_id);
  grab or allocate a slot and mark as in-use (does not do any data copying)
apr_status_t release(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)

### Directives

This module provides no directives.

Available Languages: en