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NAME

       XInitThreads, XLockDisplay, XUnlockDisplay - multi-threading support

SYNTAX

       Status XInitThreads(void);

       void XLockDisplay(Display *display);

       void XUnlockDisplay(Display *display);

ARGUMENTS

       display   Specifies the connection to the X server.

DESCRIPTION

       The XInitThreads function initializes Xlib support for concurrent threads.  This function
       must be the first Xlib function a multi-threaded program calls, and it must complete
       before any other Xlib call is made.  This function returns a nonzero status if
       initialization was successful; otherwise, it returns zero.  On systems that do not support
       threads, this function always returns zero.

       It is only necessary to call this function if multiple threads might use Xlib
       concurrently.  If all calls to Xlib functions are protected by some other access mechanism
       (for example, a mutual exclusion lock in a toolkit or through explicit client
       programming), Xlib thread initialization is not required.  It is recommended that single-
       threaded programs not call this function.

       The XLockDisplay function locks out all other threads from using the specified display.
       Other threads attempting to use the display will block until the display is unlocked by
       this thread.  Nested calls to XLockDisplay work correctly; the display will not actually
       be unlocked until XUnlockDisplay has been called the same number of times as XLockDisplay.
       This function has no effect unless Xlib was successfully initialized for threads using
       XInitThreads.

       The XUnlockDisplay function allows other threads to use the specified display again.  Any
       threads that have blocked on the display are allowed to continue.  Nested locking works
       correctly; if XLockDisplay has been called multiple times by a thread, then XUnlockDisplay
       must be called an equal number of times before the display is actually unlocked.  This
       function has no effect unless Xlib was successfully initialized for threads using
       XInitThreads.

SEE ALSO

       Xlib - C Language X Interface