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Process Locking Routines
Collaboration diagram for Process Locking Routines:

Typedefs

typedef struct apr_proc_mutex_t apr_proc_mutex_t
 

Enumerations

enum  apr_lockmech_e {
  APR_LOCK_FCNTL, APR_LOCK_FLOCK, APR_LOCK_SYSVSEM, APR_LOCK_PROC_PTHREAD,
  APR_LOCK_POSIXSEM, APR_LOCK_DEFAULT, APR_LOCK_DEFAULT_TIMED
}
 

Functions

apr_status_t apr_proc_mutex_create (apr_proc_mutex_t **mutex, const char *fname, apr_lockmech_e mech, apr_pool_t *pool)
 
apr_status_t apr_proc_mutex_child_init (apr_proc_mutex_t **mutex, const char *fname, apr_pool_t *pool)
 
apr_status_t apr_proc_mutex_lock (apr_proc_mutex_t *mutex)
 
apr_status_t apr_proc_mutex_trylock (apr_proc_mutex_t *mutex)
 
apr_status_t apr_proc_mutex_timedlock (apr_proc_mutex_t *mutex, apr_interval_time_t timeout)
 
apr_status_t apr_proc_mutex_unlock (apr_proc_mutex_t *mutex)
 
apr_status_t apr_proc_mutex_destroy (apr_proc_mutex_t *mutex)
 
apr_status_t apr_proc_mutex_cleanup (void *mutex)
 
const char * apr_proc_mutex_lockfile (apr_proc_mutex_t *mutex)
 
apr_lockmech_e apr_proc_mutex_mech (apr_proc_mutex_t *mutex)
 
const char * apr_proc_mutex_name (apr_proc_mutex_t *mutex)
 
const char * apr_proc_mutex_defname (void)
 
 APR_PERMS_SET_IMPLEMENT (proc_mutex)
 
 APR_POOL_DECLARE_ACCESSOR (proc_mutex)
 

Detailed Description

Typedef Documentation

Opaque structure representing a process mutex.

Enumeration Type Documentation

Enumerated potential types for APR process locking methods

Warning
Check APR_HAS_foo_SERIALIZE defines to see if the platform supports APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
Enumerator
APR_LOCK_FCNTL 

fcntl()

APR_LOCK_FLOCK 

flock()

APR_LOCK_SYSVSEM 

System V Semaphores

APR_LOCK_PROC_PTHREAD 

POSIX pthread process-based locking

APR_LOCK_POSIXSEM 

POSIX semaphore process-based locking

APR_LOCK_DEFAULT 

Use the default process lock

APR_LOCK_DEFAULT_TIMED 

Use the default process timed lock

Function Documentation

APR_PERMS_SET_IMPLEMENT ( proc_mutex  )

Set mutex permissions.

APR_POOL_DECLARE_ACCESSOR ( proc_mutex  )

Get the pool used by this proc_mutex.

Returns
apr_pool_t the pool
apr_status_t apr_proc_mutex_child_init ( apr_proc_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_proc_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_proc_mutex_cleanup ( void mutex)

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

Parameters
mutexthe mutex to destroy.
Note
This function is generally used to kill a cleanup on an already created mutex
apr_status_t apr_proc_mutex_create ( apr_proc_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 processes.

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
poolthe pool from which to allocate the mutex.
See Also
apr_lockmech_e
Warning
Check APR_HAS_foo_SERIALIZE defines to see if the platform supports APR_LOCK_foo. Only APR_LOCK_DEFAULT is portable.
const char* apr_proc_mutex_defname ( void  )

Display the name of the default mutex: APR_LOCK_DEFAULT

apr_status_t apr_proc_mutex_destroy ( apr_proc_mutex_t mutex)

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

Parameters
mutexthe mutex to destroy.
apr_status_t apr_proc_mutex_lock ( apr_proc_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_proc_mutex_lockfile ( apr_proc_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_proc_mutex_mech ( apr_proc_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_proc_mutex_name ( apr_proc_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_proc_mutex_timedlock ( apr_proc_mutex_t mutex,
apr_interval_time_t  timeout 
)

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 relative timeout (microseconds).
Note
A negative or nul timeout means immediate attempt, returning APR_TIMEUP without blocking if it the lock is already acquired.
apr_status_t apr_proc_mutex_trylock ( apr_proc_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_proc_mutex_unlock ( apr_proc_mutex_t mutex)

Release the lock for the given mutex.

Parameters
mutexthe mutex from which to release the lock.