Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetTimer.3 @ 615:7ec821f3cbd0
Date: Thu, 17 Apr 2003 23:27:34 -0400
From: Darrell Walisser
Subject: Yet another OS X cursor bug
The synopsis:
1. Call SDL_ShowCursor(0);
2. Call SDL_SetVideoMode();
3. Call SDL_GetEvent();
3. Call SDL_ShowCursor(1);
The result: Sometimes the cursor doesn't come back! Ack! Oddly enough,
it does come back when mousing over the dock or clicking in the menu
bar. But that's besides the point.
The reason why this is happening is a flaw in the handling of
activation/deactivation events. The short explanation is that the
HideCursor() and ShowCursor() calls must be balanced, but if the cursor
was initially hidden, HideCursor() was called again on the activate
event - so now the next ShowCursor() fails (as does the next, and the
next, for some reason).
So, here's the patch. All it does is keep track of the
HideCursor()/ShowCursor() calls so that they will always be balanced.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 20 Apr 2003 05:41:16 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_SetTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetTimer\- Set a callback to run after the specified number of milliseconds has elapsed\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_SetTimer\fP\fR(\fBUint32 interval, SDL_TimerCallback callback\fR); .SH "CALLBACK" .PP /* Function prototype for the timer callback function */ typedef Uint32 (*SDL_TimerCallback)(Uint32 interval); .SH "DESCRIPTION" .PP Set a callback to run after the specified number of milliseconds has elapsed\&. The callback function is passed the current timer interval and returns the next timer interval\&. If the returned value is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled\&. .PP To cancel a currently running timer, call \fBSDL_SetTimer(0, NULL);\fP .PP The timer callback function may run in a different thread than your main constant, and so shouldn\&'t call any functions from within itself\&. .PP The maximum resolution of this timer is 10 ms, which means that if you request a 16 ms timer, your callback will run approximately 20 ms later on an unloaded system\&. If you wanted to set a flag signaling a frame update at 30 frames per second (every 33 ms), you might set a timer for 30 ms (see example below)\&. .PP If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fBSDL_Init()\fP\&. .PP .RS \fBNote: .PP This function is kept for compatibility but has been superseded by the new timer functions \fISDL_AddTimer\fR and \fISDL_RemoveTimer\fR which support multiple timers\&. .RE .SH "EXAMPLES" .PP .PP .nf \f(CWSDL_SetTimer((33/10)*10, my_callback);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_AddTimer\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01