e14743d1 |
1 | <HTML |
2 | ><HEAD |
3 | ><TITLE |
4 | >SDL_SetEventFilter</TITLE |
5 | ><META |
6 | NAME="GENERATOR" |
7 | CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
8 | "><LINK |
9 | REL="HOME" |
10 | TITLE="SDL Library Documentation" |
11 | HREF="index.html"><LINK |
12 | REL="UP" |
13 | TITLE="Event Functions." |
14 | HREF="eventfunctions.html"><LINK |
15 | REL="PREVIOUS" |
16 | TITLE="SDL_PushEvent" |
17 | HREF="sdlpushevent.html"><LINK |
18 | REL="NEXT" |
19 | TITLE="SDL_GetEventFilter" |
20 | HREF="sdlgeteventfilter.html"></HEAD |
21 | ><BODY |
22 | CLASS="REFENTRY" |
23 | BGCOLOR="#FFF8DC" |
24 | TEXT="#000000" |
25 | LINK="#0000ee" |
26 | VLINK="#551a8b" |
27 | ALINK="#ff0000" |
28 | ><DIV |
29 | CLASS="NAVHEADER" |
30 | ><TABLE |
31 | SUMMARY="Header navigation table" |
32 | WIDTH="100%" |
33 | BORDER="0" |
34 | CELLPADDING="0" |
35 | CELLSPACING="0" |
36 | ><TR |
37 | ><TH |
38 | COLSPAN="3" |
39 | ALIGN="center" |
40 | >SDL Library Documentation</TH |
41 | ></TR |
42 | ><TR |
43 | ><TD |
44 | WIDTH="10%" |
45 | ALIGN="left" |
46 | VALIGN="bottom" |
47 | ><A |
48 | HREF="sdlpushevent.html" |
49 | ACCESSKEY="P" |
50 | >Prev</A |
51 | ></TD |
52 | ><TD |
53 | WIDTH="80%" |
54 | ALIGN="center" |
55 | VALIGN="bottom" |
56 | ></TD |
57 | ><TD |
58 | WIDTH="10%" |
59 | ALIGN="right" |
60 | VALIGN="bottom" |
61 | ><A |
62 | HREF="sdlgeteventfilter.html" |
63 | ACCESSKEY="N" |
64 | >Next</A |
65 | ></TD |
66 | ></TR |
67 | ></TABLE |
68 | ><HR |
69 | ALIGN="LEFT" |
70 | WIDTH="100%"></DIV |
71 | ><H1 |
72 | ><A |
73 | NAME="SDLSETEVENTFILTER" |
74 | ></A |
75 | >SDL_SetEventFilter</H1 |
76 | ><DIV |
77 | CLASS="REFNAMEDIV" |
78 | ><A |
79 | NAME="AEN5575" |
80 | ></A |
81 | ><H2 |
82 | >Name</H2 |
83 | >SDL_SetEventFilter -- Sets up a filter to process all events before they are posted |
84 | to the event queue.</DIV |
85 | ><DIV |
86 | CLASS="REFSYNOPSISDIV" |
87 | ><A |
88 | NAME="AEN5578" |
89 | ></A |
90 | ><H2 |
91 | >Synopsis</H2 |
92 | ><DIV |
93 | CLASS="FUNCSYNOPSIS" |
94 | ><A |
95 | NAME="AEN5579" |
96 | ></A |
97 | ><P |
98 | ></P |
99 | ><PRE |
100 | CLASS="FUNCSYNOPSISINFO" |
101 | >#include "SDL.h"</PRE |
102 | ><P |
103 | ><CODE |
104 | ><CODE |
105 | CLASS="FUNCDEF" |
106 | >void <B |
107 | CLASS="FSFUNC" |
108 | >SDL_SetEventFilter</B |
109 | ></CODE |
110 | >(SDL_EventFilter filter);</CODE |
111 | ></P |
112 | ><P |
113 | ></P |
114 | ></DIV |
115 | ></DIV |
116 | ><DIV |
117 | CLASS="REFSECT1" |
118 | ><A |
119 | NAME="AEN5585" |
120 | ></A |
121 | ><H2 |
122 | >Description</H2 |
123 | ><P |
124 | >This function sets up a filter to process all events before they are posted |
125 | to the event queue. This is a very powerful and flexible feature. The filter |
126 | is prototyped as: |
127 | <PRE |
128 | CLASS="PROGRAMLISTING" |
129 | >typedef int (*SDL_EventFilter)(const SDL_Event *event);</PRE |
130 | > |
131 | If the filter returns <SPAN |
132 | CLASS="RETURNVALUE" |
133 | >1</SPAN |
134 | >, then the event will be |
135 | added to the internal queue. If it returns <SPAN |
136 | CLASS="RETURNVALUE" |
137 | >0</SPAN |
138 | >, |
139 | then the event will be dropped from the queue. This allows selective |
140 | filtering of dynamically.</P |
141 | ><P |
142 | >There is one caveat when dealing with the <TT |
143 | CLASS="LITERAL" |
144 | >SDL_QUITEVENT</TT |
145 | > event type. The |
146 | event filter is only called when the window manager desires to close the |
147 | application window. If the event filter returns 1, then the window will |
148 | be closed, otherwise the window will remain open if possible. |
149 | If the quit event is generated by an interrupt signal, it will bypass the |
150 | internal queue and be delivered to the application at the next event poll.</P |
151 | ><DIV |
152 | CLASS="NOTE" |
153 | ><BLOCKQUOTE |
154 | CLASS="NOTE" |
155 | ><P |
156 | ><B |
157 | >Note: </B |
158 | >Events pushed onto the queue with <A |
159 | HREF="sdlpushevent.html" |
160 | ><TT |
161 | CLASS="FUNCTION" |
162 | >SDL_PushEvent</TT |
163 | ></A |
164 | > or <A |
165 | HREF="sdlpeepevents.html" |
166 | ><TT |
167 | CLASS="FUNCTION" |
168 | >SDL_PeepEvents</TT |
169 | ></A |
170 | > do not get passed through the event filter.</P |
171 | ></BLOCKQUOTE |
172 | ></DIV |
173 | ><DIV |
174 | CLASS="NOTE" |
175 | ><BLOCKQUOTE |
176 | CLASS="NOTE" |
177 | ><P |
178 | ><B |
179 | >Note: </B |
180 | ><SPAN |
181 | CLASS="emphasis" |
182 | ><I |
183 | CLASS="EMPHASIS" |
184 | >Be Careful!</I |
185 | ></SPAN |
186 | > The event filter function may run in a different thread so be careful what you do within it.</P |
187 | ></BLOCKQUOTE |
188 | ></DIV |
189 | ></DIV |
190 | ><DIV |
191 | CLASS="REFSECT1" |
192 | ><A |
193 | NAME="AEN5602" |
194 | ></A |
195 | ><H2 |
196 | >See Also</H2 |
197 | ><P |
198 | ><A |
199 | HREF="sdlevent.html" |
200 | ><SPAN |
201 | CLASS="STRUCTNAME" |
202 | >SDL_Event</SPAN |
203 | ></A |
204 | >, |
205 | <A |
206 | HREF="sdlgeteventfilter.html" |
207 | ><TT |
208 | CLASS="FUNCTION" |
209 | >SDL_GetEventFilter</TT |
210 | ></A |
211 | >, |
212 | <A |
213 | HREF="sdlpushevent.html" |
214 | ><TT |
215 | CLASS="FUNCTION" |
216 | >SDL_PushEvent</TT |
217 | ></A |
218 | ></P |
219 | ></DIV |
220 | ><DIV |
221 | CLASS="NAVFOOTER" |
222 | ><HR |
223 | ALIGN="LEFT" |
224 | WIDTH="100%"><TABLE |
225 | SUMMARY="Footer navigation table" |
226 | WIDTH="100%" |
227 | BORDER="0" |
228 | CELLPADDING="0" |
229 | CELLSPACING="0" |
230 | ><TR |
231 | ><TD |
232 | WIDTH="33%" |
233 | ALIGN="left" |
234 | VALIGN="top" |
235 | ><A |
236 | HREF="sdlpushevent.html" |
237 | ACCESSKEY="P" |
238 | >Prev</A |
239 | ></TD |
240 | ><TD |
241 | WIDTH="34%" |
242 | ALIGN="center" |
243 | VALIGN="top" |
244 | ><A |
245 | HREF="index.html" |
246 | ACCESSKEY="H" |
247 | >Home</A |
248 | ></TD |
249 | ><TD |
250 | WIDTH="33%" |
251 | ALIGN="right" |
252 | VALIGN="top" |
253 | ><A |
254 | HREF="sdlgeteventfilter.html" |
255 | ACCESSKEY="N" |
256 | >Next</A |
257 | ></TD |
258 | ></TR |
259 | ><TR |
260 | ><TD |
261 | WIDTH="33%" |
262 | ALIGN="left" |
263 | VALIGN="top" |
264 | >SDL_PushEvent</TD |
265 | ><TD |
266 | WIDTH="34%" |
267 | ALIGN="center" |
268 | VALIGN="top" |
269 | ><A |
270 | HREF="eventfunctions.html" |
271 | ACCESSKEY="U" |
272 | >Up</A |
273 | ></TD |
274 | ><TD |
275 | WIDTH="33%" |
276 | ALIGN="right" |
277 | VALIGN="top" |
278 | >SDL_GetEventFilter</TD |
279 | ></TR |
280 | ></TABLE |
281 | ></DIV |
282 | ></BODY |
283 | ></HTML |
284 | > |