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Global Locking Routines
Collaboration diagram for Global Locking Routines:

Typedefs

typedef struct apr_global_mutex_t apr_global_mutex_t
 

Functions

apr_status_t apr_global_mutex_create (apr_global_mutex_t **mutex, const char *fname, apr_lockmech_e mech, apr_pool_t *pool)
 
apr_status_t apr_global_mutex_child_init (apr_global_mutex_t **mutex, const char *fname, apr_pool_t *pool)
 
apr_status_t apr_global_mutex_lock (apr_global_mutex_t *mutex)
 
apr_status_t apr_global_mutex_trylock (apr_global_mutex_t *mutex)
 
apr_status_t apr_global_mutex_timedlock (apr_global_mutex_t *mutex, apr_time_t timeout, int absolute)
 
apr_status_t apr_global_mutex_unlock (apr_global_mutex_t *mutex)
 
apr_status_t apr_global_mutex_destroy (apr_global_mutex_t *mutex)
 
const char * apr_global_mutex_lockfile (apr_global_mutex_t *mutex)
 
apr_lockmech_e apr_global_mutex_mech (apr_global_mutex_t *mutex)
 
const char * apr_global_mutex_name (apr_global_mutex_t *mutex)
 
 APR_PERMS_SET_IMPLEMENT (global_mutex)
 
 APR_POOL_DECLARE_ACCESSOR (global_mutex)
 

Detailed Description

Typedef Documentation

Opaque global mutex structure.

Function Documentation

apr_status_t apr_global_mutex_child_init ( apr_global_mutex_t **  mutex,
const char *  fname,
apr_pool_t pool 
)

Re-open a mutex in a child process.

Parameters
mutexThe newly re-opened mutex structure.
fnameA file name to use if the mutex mechanism requires one. This argument should always be provided. The mutex code itself will determine if it should be used. This filename should be the same one that was passed to apr_global_mutex_create().
poolThe pool to operate on.
Remarks
This function must be called to maintain portability, even if the underlying lock mechanism does not require it.
apr_status_t apr_global_mutex_create ( apr_global_mutex_t **  mutex,
const char *  fname,
apr_lockmech_e  mech,
apr_pool_t pool 
)

Create and initialize a mutex that can be used to synchronize both processes and threads. Note: There is considerable overhead in using this API if only cross-process or cross-thread mutual exclusion is required. See apr_proc_mutex.h and apr_thread_mutex.h for more specialized lock routines.

Parameters
mutexthe memory address where the newly created mutex will be stored.
fnameA file name to use if the lock mechanism requires one. This argument should always be provided. The lock code itself will determine if it should be used.
mechThe mechanism to use for the interprocess lock, if any; one of
           APR_LOCK_FCNTL
           APR_LOCK_FLOCK
           APR_LOCK_SYSVSEM
           APR_LOCK_POSIXSEM
           APR_LOCK_PROC_PTHREAD
           APR_LOCK_DEFAULT     pick the default mechanism for the platform
           APR_LOCK_DEFAULT_TIMED pick the default timed mechanism
poolthe pool from which to allocate the mutex.
Warning
Check APR_HAS_foo_SERIALIZE defines to see if the platform supports APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
apr_status_t apr_global_mutex_destroy ( apr_global_mutex_t mutex)

Destroy the mutex and free the memory associated with the lock.

Parameters
mutexthe mutex to destroy.
apr_status_t apr_global_mutex_lock ( apr_global_mutex_t mutex)

Acquire the lock for the given mutex. If the mutex is already locked, the current thread will be put to sleep until the lock becomes available.

Parameters
mutexthe mutex on which to acquire the lock.
const char* apr_global_mutex_lockfile ( apr_global_mutex_t mutex)

Return the name of the lockfile for the mutex, or NULL if the mutex doesn't use a lock file

apr_lockmech_e apr_global_mutex_mech ( apr_global_mutex_t mutex)

Get the mechanism of the mutex, as it relates to the actual method used for the underlying apr_proc_mutex_t.

Parameters
mutexthe mutex to get the mechanism from.
const char* apr_global_mutex_name ( apr_global_mutex_t mutex)

Get the mechanism's name of the mutex, as it relates to the actual method used for the underlying apr_proc_mutex_t.

Parameters
mutexthe mutex to get the mechanism's name from.
apr_status_t apr_global_mutex_timedlock ( apr_global_mutex_t mutex,
apr_time_t  timeout,
int  absolute 
)

Attempt to acquire the lock for the given mutex until timeout expires. If the acquisition time outs, the call returns with APR_TIMEUP.

Parameters
mutexthe mutex on which to attempt the lock acquiring.
timeoutthe absolute time or relative timeout (microseconds)
absolutewhether the timeout given is absolute (!0) or relative (0)
apr_status_t apr_global_mutex_trylock ( apr_global_mutex_t mutex)

Attempt to acquire the lock for the given mutex. If the mutex has already been acquired, the call returns immediately with APR_EBUSY. Note: it is important that the APR_STATUS_IS_EBUSY(s) macro be used to determine if the return value was APR_EBUSY, for portability reasons.

Parameters
mutexthe mutex on which to attempt the lock acquiring.
apr_status_t apr_global_mutex_unlock ( apr_global_mutex_t mutex)

Release the lock for the given mutex.

Parameters
mutexthe mutex from which to release the lock.
APR_PERMS_SET_IMPLEMENT ( global_mutex  )

Set mutex permissions.

APR_POOL_DECLARE_ACCESSOR ( global_mutex  )

Get the pool used by this global_mutex.

Returns
apr_pool_t the pool