XInitThreads(3X11) XLIB FUNCTIONS XInitThreads(3X11)NAME
XInitThreads, XLockDisplay, XUnlockDisplay - multi-thread-
ing support
SYNTAX
Status XInitThreads();
void XLockDisplay(display)
Display *display;
void XUnlockDisplay(display)
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 com-
plete 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 sup-
port 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 initial-
ization 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 cor-
rectly; 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.
X Version 11 Release 6.4 1
XInitThreads(3X11) XLIB FUNCTIONS XInitThreads(3X11)SEE ALSO
Xlib - C Language X Interface
X Version 11 Release 6.4 2
