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 }
Functions
	APR_DECLARE (apr_status_t) apr_proc_mutex_create(apr_proc_mutex_t **mutex
	APR_DECLARE (const char *) apr_proc_mutex_lockfile(apr_proc_mutex_t *mutex)
	APR_POOL_DECLARE_ACCESSOR (proc_mutex)
Variables
const char *	fname
const char apr_lockmech_e	mech
const char apr_lockmech_e apr_pool_t *	pool

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Typedef Documentation

typedef struct apr_proc_mutex_t apr_proc_mutex_t

Opaque structure representing a process mutex.

Definition at line 54 of file apr_proc_mutex.h.

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Enumeration Type Documentation

enum apr_lockmech_e

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

Definition at line 44 of file apr_proc_mutex.h.

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Function Documentation

APR_DECLARE

(

apr_status_t

)

Create and initialize a mutex that can be used to synchronize processes.

Parameters:

mutex	the memory address where the newly created mutex will be stored.
fname	A 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.
mech	The 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
pool	the 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.

Re-open a mutex in a child process.

Parameters:

mutex	The newly re-opened mutex structure.
fname	A 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().
pool	The pool to operate on.

Remarks:

This function must be called to maintain portability, even if the underlying lock mechanism does not require it.

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:

mutex

the mutex on which to acquire the lock.

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:

mutex

the mutex on which to attempt the lock acquiring.

Release the lock for the given mutex.

Parameters:

mutex

the mutex from which to release the lock.

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

Parameters:

mutex

the mutex to destroy.

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

Parameters:

mutex

the mutex to destroy.

Note:

This function is generally used to kill a cleanup on an already created mutex

APR_DECLARE

(

const char *

)

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

Display the name of the mutex, as it relates to the actual method used. This matches the valid options for Apache's AcceptMutex directive

Parameters:

mutex

the name of the mutex

Display the name of the default mutex: APR_LOCK_DEFAULT

APR_POOL_DECLARE_ACCESSOR

(

proc_mutex

)

Get the pool used by this proc_mutex.

Returns:

apr_pool_t the pool

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Variable Documentation

const char* fname

Definition at line 80 of file apr_proc_mutex.h.

const char apr_lockmech_e mech

Definition at line 80 of file apr_proc_mutex.h.

const char apr_pool_t* pool

Definition at line 80 of file apr_proc_mutex.h.