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Diffstat (limited to 'documentation/functions.html')
| -rw-r--r-- | documentation/functions.html | 41 |
1 files changed, 40 insertions, 1 deletions
diff --git a/documentation/functions.html b/documentation/functions.html index d2a06357a..591f4edba 100644 --- a/documentation/functions.html +++ b/documentation/functions.html @@ -326,9 +326,39 @@ fair degree of accuracy: main() { Fl::add_timeout(1.0,callback); - for (;;) Fl::wait(); + return Fl::run(); }</PRE></UL> +<h3><A name=add_timeout>static void Fl::add_check(void (*cb)(void*),void*v=0)</A></h3> + +Fltk will call this callback just before it flushes the display and +waits for events. This is different than an idle callback because it +is only called once, then fltk calls the system and tells it not to +return until an event happens. + +<p>This can be used by code that wants to monitor the +application's state, such as to keep a display up to date. The +advantage of using a check callback is that it is called only when no +events are pending. If events are coming in quickly, whole blocks of +them will be processed before this is called once. This can save +significant time and avoid the application falling behind the events. + +<p>Sample code: + +<ul><pre>bool state_changed; // anything that changes the display turns this on + +void callback(void*) { + if (!state_changed) return; + state_changed = false; + do_expensive_calculation(); + widget->redraw(); +} + +main() { + Fl::add_check(1.0,callback); + return Fl::run(); +}</pre></ul> + <h3><A name=arg>static int Fl::arg(int argc, char **argv, int &i)</A></h3> Consume a single switch from <tt>argv</tt>, starting at word i. @@ -867,6 +897,15 @@ Returns true if the timeout exists and has not been called yet. Removes a timeout callback. It is harmless to remove a timeout callback that no longer exists. +<h3><A name=has_check>static int Fl::has_check(void (*cb)(void*), void* = 0)</A></h3> + +Returns true if the check exists and has not been called yet. + +<h3><A name=remove_check>static void Fl::remove_check(void (*cb)(void*), void* = 0)</A></h3> + +Removes a check callback. It is harmless to remove a check +callback that no longer exists. + <h3><A name=run>static Fl::run()</A></h3> As long as any windows are displayed this calls <tt>Fl::wait()</tt> |