view docs/man3/SDL_SetEventFilter.3 @ 914:bbf8dcc8aed6

Date: Wed, 23 Jun 2004 17:05:33 -0400 From: Chris Nelson Subject: [SDL] [Patch] WiseGroup MP-8800 / MP-8866 (PS2 Joystick) In the current cvs version, SDL doesn't handle these Playstation2 controller => USB adapters correctly, in linux. It will always assume that the maximum number of joysticks (2 in the case of the MP-8866, 4 in the case of the 8800) are plugged in. This is bad not only because it allows SDL to exaggerate the number of logical joysticks, but primarily because the joystick axes are mapped incorrectly, all over the place, such that the devices are effectively unusable unless you have the maximum number of joysticks plugged in. My changes to src/joystick/linux/SDL_sysjoystick.c build on another's previous work (which was a special case for this very joystick, actually), and fix both of these problems, as well as making the current code a little more general, to allow for others to more easily drop in code for quirky joysticks such as these. I've tested this code under 2.6.7 as well as 2.4.24... Both work as advertised (provided you load the JOYDEV linux code as a module, otherwise they won't work at all, new code or old, but that's another issue entirely). Though this sounds horribly formal, you have my permission to distribute all of my work on this issue under the LGPL. So there.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 25 Jul 2004 18:31:50 +0000
parents e5bc29de3f0a
children 546f7c1eb755
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.TH "SDL_SetEventFilter" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_SetEventFilter\- Sets up a filter to process all events before they are posted to the event queue\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBvoid \fBSDL_SetEventFilter\fP\fR(\fBSDL_EventFilter filter\fR);
.SH "DESCRIPTION"
.PP
This function sets up a filter to process all events before they are posted to the event queue\&. This is a very powerful and flexible feature\&. The filter is prototyped as: 
.PP
.nf
\f(CWtypedef int (*SDL_EventFilter)(const SDL_Event *event);\fR
.fi
.PP
 If the filter returns \fB1\fR, then the event will be added to the internal queue\&. If it returns \fB0\fR, then the event will be dropped from the queue\&. This allows selective filtering of dynamically\&.
.PP
There is one caveat when dealing with the \fBSDL_QUITEVENT\fP event type\&. The event filter is only called when the window manager desires to close the application window\&. If the event filter returns 1, then the window will be closed, otherwise the window will remain open if possible\&. If the quit event is generated by an interrupt signal, it will bypass the internal queue and be delivered to the application at the next event poll\&.
.PP
.RS
\fBNote:  
.PP
Events pushed onto the queue with \fI\fBSDL_PushEvent\fP\fR or \fI\fBSDL_PeepEvents\fP\fR do not get passed through the event filter\&.
.RE
.PP
.RS
\fBNote:  
.PP
\fIBe Careful!\fP The event filter function may run in a different thread so be careful what you do within it\&.
.RE
.SH "SEE ALSO"
.PP
\fI\fBSDL_Event\fR\fR, \fI\fBSDL_GetEventFilter\fP\fR, \fI\fBSDL_PushEvent\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59