Functions for multi-threaded applications using Libevent. More...
#include <event2/event-config.h>Go to the source code of this file.
Data Structures | |
| struct | evthread_condition_callbacks |
| This structure describes the interface a threading library uses for condition variables. More... | |
| struct | evthread_lock_callbacks |
| This structure describes the interface a threading library uses for locking. More... | |
Defines | |
| #define | EVTHREAD_CONDITION_API_VERSION 1 |
| #define | EVTHREAD_LOCK_API_VERSION 1 |
| #define | EVTHREAD_LOCKTYPE_READWRITE 2 |
| #define | EVTHREAD_LOCKTYPE_RECURSIVE 1 |
| A recursive lock is one that can be acquired multiple times at once by the same thread. | |
| #define | EVTHREAD_READ 0x08 |
| A flag passed to a locking callback when the lock was allocated as a read-write lock, and we want to acquire or release the lock for reading. | |
| #define | EVTHREAD_TRY 0x10 |
| A flag passed to a locking callback when we don't want to block waiting for the lock; if we can't get the lock immediately, we will instead return nonzero from the locking callback. | |
| #define | EVTHREAD_WRITE 0x04 |
| A flag passed to a locking callback when the lock was allocated as a read-write lock, and we want to acquire or release the lock for writing. | |
Functions | |
| void | evthread_enable_lock_debuging (void) |
| Enable debugging wrappers around the current lock callbacks. | |
| int | evthread_make_base_notifiable (struct event_base *base) |
| Make sure it's safe to tell an event base to wake up from another thread. | |
| int | evthread_set_condition_callbacks (const struct evthread_condition_callbacks *) |
| Sets a group of functions that Libevent should use for condition variables. | |
| void | evthread_set_id_callback (unsigned long(*id_fn)(void)) |
| Sets the function for determining the thread id. | |
| int | evthread_set_lock_callbacks (const struct evthread_lock_callbacks *) |
| Sets a group of functions that Libevent should use for locking. | |
Functions for multi-threaded applications using Libevent.
When using a multi-threaded application in which multiple threads add and delete events from a single event base, Libevent needs to lock its data structures.
Like the memory-management function hooks, all of the threading functions _must_ be set up before an event_base is created if you want the base to use them.
A multi-threaded application must provide locking functions to Libevent via evthread_set_locking_callback(). Libevent will invoke this callback whenever a lock needs to be acquired or released.
The total number of locks employed by Libevent can be determined via the evthread_num_locks() function. An application must provision that many locks.
If the owner of an event base is waiting for events to happen, Libevent may signal the thread via a special file descriptor to wake up. To enable this feature, an application needs to provide a thread identity function via evthread_set_id_callback().
| #define EVTHREAD_LOCKTYPE_RECURSIVE 1 |
A recursive lock is one that can be acquired multiple times at once by the same thread.
No other process can allocate the lock until the thread that has been holding it has unlocked it as many times as it locked it.
| #define EVTHREAD_READ 0x08 |
A flag passed to a locking callback when the lock was allocated as a read-write lock, and we want to acquire or release the lock for reading.
| #define EVTHREAD_TRY 0x10 |
A flag passed to a locking callback when we don't want to block waiting for the lock; if we can't get the lock immediately, we will instead return nonzero from the locking callback.
| #define EVTHREAD_WRITE 0x04 |
A flag passed to a locking callback when the lock was allocated as a read-write lock, and we want to acquire or release the lock for writing.
| void evthread_enable_lock_debuging | ( | void | ) |
Enable debugging wrappers around the current lock callbacks.
If Libevent makes one of several common locking errors, exit with an assertion failure.
| int evthread_make_base_notifiable | ( | struct event_base * | base ) |
Make sure it's safe to tell an event base to wake up from another thread.
or a signal handler.
| int evthread_set_condition_callbacks | ( | const struct evthread_condition_callbacks * | ) |
Sets a group of functions that Libevent should use for condition variables.
For full information on the required callback API, see the documentation for the individual members of evthread_condition_callbacks.
Note that if you're using Windows or the Pthreads threading library, you probably shouldn't call this function; instead, use evthread_use_windows_threads() or evthread_use_posix_threads() if you can.
| void evthread_set_id_callback | ( | unsigned long(*)(void) | id_fn ) |
Sets the function for determining the thread id.
| base | the event base for which to set the id function |
| id_fn | the identify function Libevent should invoke to determine the identity of a thread. |
| int evthread_set_lock_callbacks | ( | const struct evthread_lock_callbacks * | ) |
Sets a group of functions that Libevent should use for locking.
For full information on the required callback API, see the documentation for the individual members of evthread_lock_callbacks.
Note that if you're using Windows or the Pthreads threading library, you probably shouldn't call this function; instead, use evthread_use_windows_threads() or evthread_use_posix_threads() if you can.
1.7.2