Mercurial > sdl-ios-xcode
annotate docs/html/sdlpushevent.html @ 765:4c2ba6161939
Editors Note: The original patch was modified to use SDL_Delay() instead of
nanosleep because nanosleep may not be portable to all systems
using SDL with the ALSA backend. This may be a moot point with
the switch to blocking writes anyway...
Date: Sat, 27 Dec 2003 21:47:36 +0100
From: Michel Daenzer
To: Debian Bug Tracking System
Subject: [SDL] Bug#225252: [PATCH] ALSA fixes
Package: libsdl1.2debian-all
Version: 1.2.6-2
Severity: normal
Tags: patch
For SDL 1.2.6, the ALSA backend was changed to call snd_pcm_open() with
SND_PCM_NONBLOCK. That's a good idea per se, however, it causes high CPU
usage, interrupted sound and stuttering in some games here. Taking a nanosleep
whenever snd_pcm_writei() returns -EAGAIN fixes this, but I think it's more
efficient to use blocking mode for the actual sound playback. Feedback from the
SDL and ALSA lists appreciated.
The patch also fixes the default ALSA device to be used.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 04 Jan 2004 15:40:50 +0000 |
| parents | e5bc29de3f0a |
| children | 355632dca928 |
| rev | line source |
|---|---|
| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >SDL_PushEvent</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
|
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.64 |
| 0 | 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_WaitEvent" | |
| 17 HREF="sdlwaitevent.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="SDL_SetEventFilter" | |
| 20 HREF="sdlseteventfilter.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 WIDTH="100%" | |
| 32 BORDER="0" | |
| 33 CELLPADDING="0" | |
| 34 CELLSPACING="0" | |
| 35 ><TR | |
| 36 ><TH | |
| 37 COLSPAN="3" | |
| 38 ALIGN="center" | |
| 39 >SDL Library Documentation</TH | |
| 40 ></TR | |
| 41 ><TR | |
| 42 ><TD | |
| 43 WIDTH="10%" | |
| 44 ALIGN="left" | |
| 45 VALIGN="bottom" | |
| 46 ><A | |
| 47 HREF="sdlwaitevent.html" | |
| 48 >Prev</A | |
| 49 ></TD | |
| 50 ><TD | |
| 51 WIDTH="80%" | |
| 52 ALIGN="center" | |
| 53 VALIGN="bottom" | |
| 54 ></TD | |
| 55 ><TD | |
| 56 WIDTH="10%" | |
| 57 ALIGN="right" | |
| 58 VALIGN="bottom" | |
| 59 ><A | |
| 60 HREF="sdlseteventfilter.html" | |
| 61 >Next</A | |
| 62 ></TD | |
| 63 ></TR | |
| 64 ></TABLE | |
| 65 ><HR | |
| 66 ALIGN="LEFT" | |
| 67 WIDTH="100%"></DIV | |
| 68 ><H1 | |
| 69 ><A | |
| 70 NAME="SDLPUSHEVENT" | |
| 71 >SDL_PushEvent</A | |
| 72 ></H1 | |
| 73 ><DIV | |
| 74 CLASS="REFNAMEDIV" | |
| 75 ><A | |
|
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76 NAME="AEN5148" |
| 0 | 77 ></A |
| 78 ><H2 | |
| 79 >Name</H2 | |
| 80 >SDL_PushEvent -- Pushes an event onto the event queue</DIV | |
| 81 ><DIV | |
| 82 CLASS="REFSYNOPSISDIV" | |
| 83 ><A | |
|
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84 NAME="AEN5151" |
| 0 | 85 ></A |
| 86 ><H2 | |
| 87 >Synopsis</H2 | |
| 88 ><DIV | |
| 89 CLASS="FUNCSYNOPSIS" | |
| 90 ><A | |
|
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91 NAME="AEN5152" |
| 0 | 92 ></A |
| 93 ><P | |
| 94 ></P | |
| 95 ><PRE | |
| 96 CLASS="FUNCSYNOPSISINFO" | |
| 97 >#include "SDL.h"</PRE | |
| 98 ><P | |
| 99 ><CODE | |
| 100 ><CODE | |
| 101 CLASS="FUNCDEF" | |
| 102 >int <B | |
| 103 CLASS="FSFUNC" | |
| 104 >SDL_PushEvent</B | |
| 105 ></CODE | |
| 106 >(SDL_Event *event);</CODE | |
| 107 ></P | |
| 108 ><P | |
| 109 ></P | |
| 110 ></DIV | |
| 111 ></DIV | |
| 112 ><DIV | |
| 113 CLASS="REFSECT1" | |
| 114 ><A | |
|
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115 NAME="AEN5158" |
| 0 | 116 ></A |
| 117 ><H2 | |
| 118 >Description</H2 | |
| 119 ><P | |
| 120 >The event queue can actually be used as a two way communication channel. Not only can events be read from the queue, but the user can also push their own events onto it. <TT | |
| 121 CLASS="PARAMETER" | |
| 122 ><I | |
| 123 >event</I | |
| 124 ></TT | |
| 125 > is a pointer to the event structure you wish to push onto the queue.</P | |
| 126 ><DIV | |
| 127 CLASS="NOTE" | |
| 128 ><BLOCKQUOTE | |
| 129 CLASS="NOTE" | |
| 130 ><P | |
| 131 ><B | |
| 132 >Note: </B | |
| 133 >Pushing device input events onto the queue doesn't modify the state of the device within SDL.</P | |
| 134 ></BLOCKQUOTE | |
| 135 ></DIV | |
| 136 ></DIV | |
| 137 ><DIV | |
| 138 CLASS="REFSECT1" | |
| 139 ><A | |
|
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140 NAME="AEN5164" |
| 0 | 141 ></A |
| 142 ><H2 | |
| 143 >Return Value</H2 | |
| 144 ><P | |
| 145 >Returns <SPAN | |
| 146 CLASS="RETURNVALUE" | |
| 147 >0</SPAN | |
| 148 > on success or <SPAN | |
| 149 CLASS="RETURNVALUE" | |
| 150 >-1</SPAN | |
| 151 > if the event couldn't be pushed.</P | |
| 152 ></DIV | |
| 153 ><DIV | |
| 154 CLASS="REFSECT1" | |
| 155 ><A | |
|
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156 NAME="AEN5169" |
| 0 | 157 ></A |
| 158 ><H2 | |
| 159 >Examples</H2 | |
| 160 ><P | |
| 161 >See <A | |
| 162 HREF="sdlevent.html" | |
| 163 ><SPAN | |
| 164 CLASS="STRUCTNAME" | |
| 165 >SDL_Event</SPAN | |
| 166 ></A | |
| 167 >.</P | |
| 168 ></DIV | |
| 169 ><DIV | |
| 170 CLASS="REFSECT1" | |
| 171 ><A | |
|
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172 NAME="AEN5174" |
| 0 | 173 ></A |
| 174 ><H2 | |
| 175 >See Also</H2 | |
| 176 ><P | |
| 177 ><A | |
| 178 HREF="sdlpollevent.html" | |
| 179 ><TT | |
| 180 CLASS="FUNCTION" | |
| 181 >SDL_PollEvent</TT | |
| 182 ></A | |
| 183 >, | |
| 184 <A | |
| 185 HREF="sdlpeepevents.html" | |
| 186 ><TT | |
| 187 CLASS="FUNCTION" | |
| 188 >SDL_PeepEvents</TT | |
| 189 ></A | |
| 190 >, | |
| 191 <A | |
| 192 HREF="sdlevent.html" | |
| 193 ><SPAN | |
| 194 CLASS="STRUCTNAME" | |
| 195 >SDL_Event</SPAN | |
| 196 ></A | |
| 197 ></P | |
| 198 ></DIV | |
| 199 ><DIV | |
| 200 CLASS="NAVFOOTER" | |
| 201 ><HR | |
| 202 ALIGN="LEFT" | |
| 203 WIDTH="100%"><TABLE | |
| 204 WIDTH="100%" | |
| 205 BORDER="0" | |
| 206 CELLPADDING="0" | |
| 207 CELLSPACING="0" | |
| 208 ><TR | |
| 209 ><TD | |
| 210 WIDTH="33%" | |
| 211 ALIGN="left" | |
| 212 VALIGN="top" | |
| 213 ><A | |
| 214 HREF="sdlwaitevent.html" | |
| 215 >Prev</A | |
| 216 ></TD | |
| 217 ><TD | |
| 218 WIDTH="34%" | |
| 219 ALIGN="center" | |
| 220 VALIGN="top" | |
| 221 ><A | |
| 222 HREF="index.html" | |
| 223 >Home</A | |
| 224 ></TD | |
| 225 ><TD | |
| 226 WIDTH="33%" | |
| 227 ALIGN="right" | |
| 228 VALIGN="top" | |
| 229 ><A | |
| 230 HREF="sdlseteventfilter.html" | |
| 231 >Next</A | |
| 232 ></TD | |
| 233 ></TR | |
| 234 ><TR | |
| 235 ><TD | |
| 236 WIDTH="33%" | |
| 237 ALIGN="left" | |
| 238 VALIGN="top" | |
| 239 >SDL_WaitEvent</TD | |
| 240 ><TD | |
| 241 WIDTH="34%" | |
| 242 ALIGN="center" | |
| 243 VALIGN="top" | |
| 244 ><A | |
| 245 HREF="eventfunctions.html" | |
| 246 >Up</A | |
| 247 ></TD | |
| 248 ><TD | |
| 249 WIDTH="33%" | |
| 250 ALIGN="right" | |
| 251 VALIGN="top" | |
| 252 >SDL_SetEventFilter</TD | |
| 253 ></TR | |
| 254 ></TABLE | |
| 255 ></DIV | |
| 256 ></BODY | |
| 257 ></HTML | |
| 258 > |