Mercurial > sdl-ios-xcode
annotate docs/html/guidebasicsinit.html @ 4137:be12463f31ea SDL-1.2
Date: Sat, 2 Feb 2008 22:08:05 +0100
From: Marcus von Appen
To: sdl@lists.libsdl.org
Subject: [SDL] [Patch] SDL-1.2 SDL_revcpy() asm patch for the cld flag
Hi,
as reported through the FreeBSD bug tracking system in SDL 1.2.13 (and
in the 1.2 branch, if I see that correctly) the SDL_revcpy() macro sets
the direction flag (std), but does not clear it afterwards (cld), which
is wrong according to the GCC and SYS V specs. This can cause some
weird side effects, which in turn can lead to memory corruption.
You can read the full report with a detailed description and test
program at http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/120052
Attached is the submitted patch, which fixes the issue.
Regards
Marcus
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Mon, 04 Feb 2008 17:22:56 +0000 |
| parents | 355632dca928 |
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| rev | line source |
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| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >Initializing SDL</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="The Basics" | |
| 14 HREF="guidethebasics.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="The Basics" | |
| 17 HREF="guidethebasics.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="Graphics and Video" | |
| 20 HREF="guidevideo.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="SECT1" | |
| 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="guidethebasics.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 >Chapter 1. The Basics</TD | |
| 57 ><TD | |
| 58 WIDTH="10%" | |
| 59 ALIGN="right" | |
| 60 VALIGN="bottom" | |
| 61 ><A | |
| 62 HREF="guidevideo.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 ><DIV | |
| 72 CLASS="SECT1" | |
| 73 ><H1 | |
| 74 CLASS="SECT1" | |
| 75 ><A | |
| 76 NAME="GUIDEBASICSINIT" | |
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77 ></A |
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78 >Initializing SDL</H1 |
| 0 | 79 ><P |
| 80 >SDL is composed of eight subsystems - Audio, CDROM, Event Handling, File I/O, Joystick Handling, Threading, Timers and Video. Before you can use any of these subsystems they must be initialized by calling <A | |
| 81 HREF="sdlinit.html" | |
| 82 ><TT | |
| 83 CLASS="FUNCTION" | |
| 84 >SDL_Init</TT | |
| 85 ></A | |
| 86 > (or <A | |
| 87 HREF="sdlinitsubsystem.html" | |
| 88 ><TT | |
| 89 CLASS="FUNCTION" | |
| 90 >SDL_InitSubSystem</TT | |
| 91 ></A | |
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92 >). <TT |
| 0 | 93 CLASS="FUNCTION" |
| 94 >SDL_Init</TT | |
| 95 > must be called before any other SDL function. It automatically initializes the Event Handling, File I/O and Threading subsystems and it takes a parameter specifying which other subsystems to initialize. So, to initialize the default subsystems and the Video subsystems you would call: | |
| 96 <PRE | |
| 97 CLASS="PROGRAMLISTING" | |
| 98 > SDL_Init ( SDL_INIT_VIDEO );</PRE | |
| 99 > | |
| 100 To initialize the default subsystems, the Video subsystem and the Timers subsystem you would call: | |
| 101 <PRE | |
| 102 CLASS="PROGRAMLISTING" | |
| 103 > SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE | |
| 104 ></P | |
| 105 ><P | |
| 106 ><TT | |
| 107 CLASS="FUNCTION" | |
| 108 >SDL_Init</TT | |
| 109 > is complemented by <A | |
| 110 HREF="sdlquit.html" | |
| 111 ><TT | |
| 112 CLASS="FUNCTION" | |
| 113 >SDL_Quit</TT | |
| 114 ></A | |
| 115 > (and <A | |
| 116 HREF="sdlquitsubsystem.html" | |
| 117 ><TT | |
| 118 CLASS="FUNCTION" | |
| 119 >SDL_QuitSubSystem</TT | |
| 120 ></A | |
| 121 >). <TT | |
| 122 CLASS="FUNCTION" | |
| 123 >SDL_Quit</TT | |
| 124 > shuts down all subsystems, including the default ones. It should always be called before a SDL application exits.</P | |
| 125 ><P | |
| 126 >With <TT | |
| 127 CLASS="FUNCTION" | |
| 128 >SDL_Init</TT | |
| 129 > and <TT | |
| 130 CLASS="FUNCTION" | |
| 131 >SDL_Quit</TT | |
| 132 > firmly embedded in your programmers toolkit you can write your first and most basic SDL application. However, we must be prepare to handle errors. Many SDL functions return a value and indicates whether the function has succeeded or failed, <TT | |
| 133 CLASS="FUNCTION" | |
| 134 >SDL_Init</TT | |
| 135 >, for instance, returns -1 if it could not initialize a subsystem. SDL provides a useful facility that allows you to determine exactly what the problem was, every time an error occurs within SDL an error message is stored which can be retrieved using <TT | |
| 136 CLASS="FUNCTION" | |
| 137 >SDL_GetError</TT | |
| 138 >. Use this often, you can never know too much about an error.</P | |
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139 ><DIV |
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140 CLASS="EXAMPLE" |
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141 ><A |
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142 NAME="AEN60" |
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143 ></A |
| 0 | 144 ><P |
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145 ><B |
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146 >Example 1-1. Initializing SDL</B |
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147 ></P |
| 0 | 148 ><PRE |
| 149 CLASS="PROGRAMLISTING" | |
| 150 >#include "SDL.h" /* All SDL App's need this */ | |
| 151 #include <stdio.h> | |
| 152 | |
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153 int main(int argc, char *argv[]) { |
| 0 | 154 |
| 155 printf("Initializing SDL.\n"); | |
| 156 | |
| 157 /* Initialize defaults, Video and Audio */ | |
| 158 if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) { | |
| 159 printf("Could not initialize SDL: %s.\n", SDL_GetError()); | |
| 160 exit(-1); | |
| 161 } | |
| 162 | |
| 163 printf("SDL initialized.\n"); | |
| 164 | |
| 165 printf("Quiting SDL.\n"); | |
| 166 | |
| 167 /* Shutdown all subsystems */ | |
| 168 SDL_Quit(); | |
| 169 | |
| 170 printf("Quiting....\n"); | |
| 171 | |
| 172 exit(0); | |
| 173 } </PRE | |
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174 ></DIV |
| 0 | 175 ></DIV |
| 176 ><DIV | |
| 177 CLASS="NAVFOOTER" | |
| 178 ><HR | |
| 179 ALIGN="LEFT" | |
| 180 WIDTH="100%"><TABLE | |
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181 SUMMARY="Footer navigation table" |
| 0 | 182 WIDTH="100%" |
| 183 BORDER="0" | |
| 184 CELLPADDING="0" | |
| 185 CELLSPACING="0" | |
| 186 ><TR | |
| 187 ><TD | |
| 188 WIDTH="33%" | |
| 189 ALIGN="left" | |
| 190 VALIGN="top" | |
| 191 ><A | |
| 192 HREF="guidethebasics.html" | |
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193 ACCESSKEY="P" |
| 0 | 194 >Prev</A |
| 195 ></TD | |
| 196 ><TD | |
| 197 WIDTH="34%" | |
| 198 ALIGN="center" | |
| 199 VALIGN="top" | |
| 200 ><A | |
| 201 HREF="index.html" | |
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202 ACCESSKEY="H" |
| 0 | 203 >Home</A |
| 204 ></TD | |
| 205 ><TD | |
| 206 WIDTH="33%" | |
| 207 ALIGN="right" | |
| 208 VALIGN="top" | |
| 209 ><A | |
| 210 HREF="guidevideo.html" | |
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211 ACCESSKEY="N" |
| 0 | 212 >Next</A |
| 213 ></TD | |
| 214 ></TR | |
| 215 ><TR | |
| 216 ><TD | |
| 217 WIDTH="33%" | |
| 218 ALIGN="left" | |
| 219 VALIGN="top" | |
| 220 >The Basics</TD | |
| 221 ><TD | |
| 222 WIDTH="34%" | |
| 223 ALIGN="center" | |
| 224 VALIGN="top" | |
| 225 ><A | |
| 226 HREF="guidethebasics.html" | |
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227 ACCESSKEY="U" |
| 0 | 228 >Up</A |
| 229 ></TD | |
| 230 ><TD | |
| 231 WIDTH="33%" | |
| 232 ALIGN="right" | |
| 233 VALIGN="top" | |
| 234 >Graphics and Video</TD | |
| 235 ></TR | |
| 236 ></TABLE | |
| 237 ></DIV | |
| 238 ></BODY | |
| 239 ></HTML | |
| 240 > |