The purpose of a TQMutex is to protect an object, data structure or section of code so that only one thread can access it at a time (This is similar to the Java \fCsynchronized\fR keyword). For example, say there is a method which prints a message to the user on two lines:
Then only one thread can modify \fCnumber\fR at any given time and the result is correct. This is a trivial example, of course, but applies to any other case where things need to happen in a particular sequence.
.PP
When you call lock() in a thread, other threads that try to call lock() in the same place will block until the thread that got the lock calls unlock(). A non-blocking alternative to lock() is tryLock().
Constructs a new mutex. The mutex is created in an unlocked state. A recursive mutex is created if \fIrecursive\fR is TRUE; a normal mutex is created if \fIrecursive\fR is FALSE (the default). With a recursive mutex, a thread can lock the same mutex multiple times and it will not be unlocked until a corresponding number of unlock() calls have been made.
Returns TRUE if the mutex is locked by another thread; otherwise returns FALSE.
.PP
\fBWarning:\fR Due to differing implementations of recursive mutexes on various platforms, calling this function from the same thread that previously locked the mutex will return undefined results.
Attempt to lock the mutex. If the lock was obtained, this function returns TRUE. If another thread has locked the mutex, this function returns FALSE, instead of waiting for the mutex to become available, i.e. it does not block.
.PP
If the lock was obtained, the mutex must be unlocked with unlock() before another thread can successfully lock it.
Unlocks the mutex. Attempting to unlock a mutex in a different thread to the one that locked it results in an error. Unlocking a mutex that is not locked results in undefined behaviour (varies between different Operating Systems' thread implementations).
