Mercurial > sdl-ios-xcode
annotate docs/html/sdlsemwait.html @ 1629:ef4a796e7f24
Fixed bug #55
From Christian Walther:
When writing my patch for #12, I ended up doing all sorts of changes to the way
application/window activating/deactivating is handled in the Quartz backend,
resulting in the attached patch. It does make the code a bit cleaner IMHO, but
as it might be regarded as a case of "if it ain't broken, don't fix it" I'd
like to hear other people's opinion about it. Please shout if some change
strikes you as unnecessary or wrong, and I'll explain the reasons behind it. As
far as I tested it, it does not introduce any new bugs, but I may well have
missed some.
- The most fundamental change (that triggered most of the others) is irrelevant
for the usual single-window SDL applications, it only affects the people who
are crazy enough to display other Cocoa windows alongside the SDL window (I'm
actually doing this currently, although the additional window only displays
debugging info and won't be present in the final product): Before, some things
were done on the application becoming active, some on the window becoming key,
and some on the window becoming main. Conceptually, all these actions belong to
the window becoming key, so that's what I implemented. However, since in a
single-window application these three events always happen together, the
previous implementation "ain't broken".
- This slightly changed the meaning of the SDL_APPMOUSEFOCUS flag from
SDL_GetAppState(): Before, it meant "window is main and mouse is inside window
(or mode is fullscreen)". Now, it means "window is key and mouse is inside
window (or mode is fullscreen)". It makes more sense to me that way. (See
http://developer.apple.com/documentation/Cocoa/Conceptual/WinPanel/Concepts/ChangingMainKeyWindow.html
for a discussion of what key and main windows are.) The other two flags are
unchanged: SDL_APPACTIVE = application is not hidden and window is not
minimized, SDL_APPINPUTFOCUS = window is key (or mode is fullscreen).
- As a side effect, the reorganization fixes the following two issues (and
maybe others) (but they could also be fixed in less invasive ways):
* A regression that was introduced in revision 1.42 of SDL_QuartzVideo.m
(http://libsdl.org/cgi/cvsweb.cgi/SDL12/src/video/quartz/SDL_QuartzVideo.m.diff?r1=1.41&r2=1.42)
(from half-desirable to undesirable behavior):
Situation: While in windowed mode, hide the cursor using
SDL_ShowCursor(SDL_DISABLE), move the mouse outside of the window so that the
cursor becomes visible again, and SDL_SetVideoMode() to a fullscreen mode.
What happened before revision 1.42: The cursor is visible, but becomes
invisible as soon as the mouse is moved (half-desirable).
What happens in revision 1.42 and after (including current CVS): The cursor is
visible and stays visible (undesirable).
What happens after my patch: The cursor is invisible from the beginning
(desirable).
* When the cursor is hidden and grabbed, switch away from the application using
cmd-tab (which ungrabs and makes the cursor visible), move the cursor outside
of the SDL window, then cmd-tab back to the application. In 1.2.8 and in the
current CVS, the cursor is re-grabbed, but it stays visible (immovable in the
middle of the window). With my patch, the cursor is correctly re-grabbed and
hidden. (For some reason, it still doesn't work correctly if you switch back to
the application using the dock instead of cmd-tab. I haven't been able to
figure out why. I can step over [NSCursor hide] being called in the debugger,
but it seems to have no effect.)
- The patch includes my patch for #12 (it was easier to obtain using cvs diff
that way). If you apply both of them, you will end up with 6 duplicate lines in
SDL_QuartzEvents.m.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Thu, 13 Apr 2006 14:17:48 +0000 |
parents | 355632dca928 |
children |
rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_SemWait</TITLE | |
5 ><META | |
6 NAME="GENERATOR" | |
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
0 | 8 "><LINK |
9 REL="HOME" | |
10 TITLE="SDL Library Documentation" | |
11 HREF="index.html"><LINK | |
12 REL="UP" | |
13 TITLE="Multi-threaded Programming" | |
14 HREF="thread.html"><LINK | |
15 REL="PREVIOUS" | |
16 TITLE="SDL_DestroySemaphore" | |
17 HREF="sdldestroysemaphore.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_SemTryWait" | |
20 HREF="sdlsemtrywait.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 | |
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31 SUMMARY="Header navigation table" |
0 | 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="sdldestroysemaphore.html" | |
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49 ACCESSKEY="P" |
0 | 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="sdlsemtrywait.html" | |
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63 ACCESSKEY="N" |
0 | 64 >Next</A |
65 ></TD | |
66 ></TR | |
67 ></TABLE | |
68 ><HR | |
69 ALIGN="LEFT" | |
70 WIDTH="100%"></DIV | |
71 ><H1 | |
72 ><A | |
73 NAME="SDLSEMWAIT" | |
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74 ></A |
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75 >SDL_SemWait</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN8023" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_SemWait -- Lock a semaphore and suspend the thread if the semaphore value is zero.</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN8026" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN8027" |
0 | 95 ></A |
96 ><P | |
97 ></P | |
98 ><PRE | |
99 CLASS="FUNCSYNOPSISINFO" | |
100 >#include "SDL.h" | |
101 #include "SDL_thread.h"</PRE | |
102 ><P | |
103 ><CODE | |
104 ><CODE | |
105 CLASS="FUNCDEF" | |
106 >int <B | |
107 CLASS="FSFUNC" | |
108 >SDL_SemWait</B | |
109 ></CODE | |
110 >(SDL_sem *sem);</CODE | |
111 ></P | |
112 ><P | |
113 ></P | |
114 ></DIV | |
115 ></DIV | |
116 ><DIV | |
117 CLASS="REFSECT1" | |
118 ><A | |
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119 NAME="AEN8033" |
0 | 120 ></A |
121 ><H2 | |
122 >Description</H2 | |
123 ><P | |
124 ><TT | |
125 CLASS="FUNCTION" | |
126 >SDL_SemWait()</TT | |
127 > suspends the calling thread until either | |
128 the semaphore pointed to by <TT | |
129 CLASS="PARAMETER" | |
130 ><I | |
131 >sem</I | |
132 ></TT | |
133 > has a positive value, | |
134 the call is interrupted by a signal or error. If the call is successful it | |
135 will atomically decrement the semaphore value.</P | |
136 ><P | |
137 >After <TT | |
138 CLASS="FUNCTION" | |
139 >SDL_SemWait()</TT | |
140 > is successful, the semaphore | |
141 can be released and its count atomically incremented by a successful call to | |
142 <A | |
143 HREF="sdlsempost.html" | |
144 >SDL_SemPost</A | |
145 >.</P | |
146 ></DIV | |
147 ><DIV | |
148 CLASS="REFSECT1" | |
149 ><A | |
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150 NAME="AEN8041" |
0 | 151 ></A |
152 ><H2 | |
153 >Return Value</H2 | |
154 ><P | |
155 >Returns <SPAN | |
156 CLASS="RETURNVALUE" | |
157 >0</SPAN | |
158 > if successful or | |
159 <SPAN | |
160 CLASS="RETURNVALUE" | |
161 >-1</SPAN | |
162 > if there was an error (leaving the semaphore unchanged).</P | |
163 ></DIV | |
164 ><DIV | |
165 CLASS="REFSECT1" | |
166 ><A | |
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167 NAME="AEN8046" |
0 | 168 ></A |
169 ><H2 | |
170 >Examples</H2 | |
171 ><P | |
172 ><PRE | |
173 CLASS="PROGRAMLISTING" | |
174 >if (SDL_SemWait(my_sem) == -1) { | |
175 return WAIT_FAILED; | |
176 } | |
177 | |
178 ... | |
179 | |
180 SDL_SemPost(my_sem);</PRE | |
181 ></P | |
182 ></DIV | |
183 ><DIV | |
184 CLASS="REFSECT1" | |
185 ><A | |
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186 NAME="AEN8050" |
0 | 187 ></A |
188 ><H2 | |
189 >See Also</H2 | |
190 ><P | |
191 ><A | |
192 HREF="sdlcreatesemaphore.html" | |
193 ><TT | |
194 CLASS="FUNCTION" | |
195 >SDL_CreateSemaphore</TT | |
196 ></A | |
197 >, | |
198 <A | |
199 HREF="sdldestroysemaphore.html" | |
200 ><TT | |
201 CLASS="FUNCTION" | |
202 >SDL_DestroySemaphore</TT | |
203 ></A | |
204 >, | |
205 <A | |
206 HREF="sdlsemtrywait.html" | |
207 ><TT | |
208 CLASS="FUNCTION" | |
209 >SDL_SemTryWait</TT | |
210 ></A | |
211 >, | |
212 <A | |
213 HREF="sdlsemwaittimeout.html" | |
214 ><TT | |
215 CLASS="FUNCTION" | |
216 >SDL_SemWaitTimeout</TT | |
217 ></A | |
218 >, | |
219 <A | |
220 HREF="sdlsempost.html" | |
221 ><TT | |
222 CLASS="FUNCTION" | |
223 >SDL_SemPost</TT | |
224 ></A | |
225 >, | |
226 <A | |
227 HREF="sdlsemvalue.html" | |
228 ><TT | |
229 CLASS="FUNCTION" | |
230 >SDL_SemValue</TT | |
231 ></A | |
232 ></P | |
233 ></DIV | |
234 ><DIV | |
235 CLASS="NAVFOOTER" | |
236 ><HR | |
237 ALIGN="LEFT" | |
238 WIDTH="100%"><TABLE | |
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239 SUMMARY="Footer navigation table" |
0 | 240 WIDTH="100%" |
241 BORDER="0" | |
242 CELLPADDING="0" | |
243 CELLSPACING="0" | |
244 ><TR | |
245 ><TD | |
246 WIDTH="33%" | |
247 ALIGN="left" | |
248 VALIGN="top" | |
249 ><A | |
250 HREF="sdldestroysemaphore.html" | |
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251 ACCESSKEY="P" |
0 | 252 >Prev</A |
253 ></TD | |
254 ><TD | |
255 WIDTH="34%" | |
256 ALIGN="center" | |
257 VALIGN="top" | |
258 ><A | |
259 HREF="index.html" | |
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260 ACCESSKEY="H" |
0 | 261 >Home</A |
262 ></TD | |
263 ><TD | |
264 WIDTH="33%" | |
265 ALIGN="right" | |
266 VALIGN="top" | |
267 ><A | |
268 HREF="sdlsemtrywait.html" | |
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269 ACCESSKEY="N" |
0 | 270 >Next</A |
271 ></TD | |
272 ></TR | |
273 ><TR | |
274 ><TD | |
275 WIDTH="33%" | |
276 ALIGN="left" | |
277 VALIGN="top" | |
278 >SDL_DestroySemaphore</TD | |
279 ><TD | |
280 WIDTH="34%" | |
281 ALIGN="center" | |
282 VALIGN="top" | |
283 ><A | |
284 HREF="thread.html" | |
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285 ACCESSKEY="U" |
0 | 286 >Up</A |
287 ></TD | |
288 ><TD | |
289 WIDTH="33%" | |
290 ALIGN="right" | |
291 VALIGN="top" | |
292 >SDL_SemTryWait</TD | |
293 ></TR | |
294 ></TABLE | |
295 ></DIV | |
296 ></BODY | |
297 ></HTML | |
298 > |