tttk_block_while(library call) tttk_block_while(library call)
NAMEtttk_block_while — block while a counter is greater than zero
SYNOPSIS
#include <Tt/tttk.h>
Tt_status tttk_block_while(
XtAppContext app2run,
const int *blocked,
int ms_timeout);
DESCRIPTION
The tttk_block_while function is used to process asynchronous events,
such as ToolTalk messages or window system events, while waiting for a
condition or timeout.
If app2run is not zero, then an event loop is run for that application
context, by repeatedly calling XtAppProcessEvent(3) with ms_timeout
being effected using XtAppAddTimeOut(3). If app2run is zero, then the
file descriptor (as returned by tt_fd(3)) of the default procid is
polled (using the poll(2) function) and tttk_Xt_input_handler(3) is
called whenever the file descriptor is active.
If blocked is zero, then tttk_block_while runs until ms_timeout occurs.
If blocked is non-zero, then the loop is run until either ms_timeout
occurs, or *blocked is less than 1.
If ms_timeout is zero, tttk_block_while checks once for events, pro‐
cesses the first one, and then returns. If ms_timeout is negative, no
timeout is in effect.
RETURN VALUE
Upon successful completion, the tttk_block_while function returns the
status of the operation as one of the following Tt_status values:
TT_OK The operation completed successfully.
TT_DESKTOP_ETIMEDOUT
The timeout occurred within ms_timeout milliseconds, or
ms_timeout was zero and no input was available.
TT_DESKTOP_EINTR
The app2run argument was zero, and poll(2) was interrupted by
a signal.
TT_DESKTOP_EAGAIN
The app2run argument was zero, and poll(2) returned EAGAIN.
If app2run is not zero and ms_timeout is negative, then
tttk_block_while will only return when *blocked is less than 1, with
TT_OK being returned.
If app2run is not zero, ms_timeout is negative, and blocked is zero,
then tttk_block_while behaves equivalent to XtAppMainLoop(3), and will
never return.
APPLICATION USAGE
If app2run is zero, then only messaging events for the default procid
will be serviced. Events for other procids will be blocked, as will
window system events, so that the graphical user interface of the
application will not update itself even, for example, after expose
events.
On the other hand, if the application passes its Xt context in as
app2run, then window system events will continue to be handled, as will
message activity for all procids for which an XtAppAddInput(3) has been
done. Since the window system event loop is fully operational in this
case, the application should take care to disable any user interface
controls that the user should not operate while the application is
waiting for tttk_block_while to return.
SEE ALSO
Tt/tttk.h - Tttttk(5), tttk_Xt_input_handler(3); poll(2), XtAppPend‐
ing(3), XtAppAddTimeOut(3), XtAppNextEvent(3), XtDispatchEvent(3).
tttk_block_while(library call)
