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Initial revision
author Sam Lantinga <slouken@lokigames.com>
date Thu, 26 Apr 2001 16:45:43 +0000
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children 55f1f1b3e27d
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1 <HTML
2 ><HEAD
3 ><TITLE
4 >Initializing SDL</TITLE
5 ><META
6 NAME="GENERATOR"
7 CONTENT="Modular DocBook HTML Stylesheet Version 1.61
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
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="guidethebasics.html"
48 >Prev</A
49 ></TD
50 ><TD
51 WIDTH="80%"
52 ALIGN="center"
53 VALIGN="bottom"
54 >Chapter 1. The Basics</TD
55 ><TD
56 WIDTH="10%"
57 ALIGN="right"
58 VALIGN="bottom"
59 ><A
60 HREF="guidevideo.html"
61 >Next</A
62 ></TD
63 ></TR
64 ></TABLE
65 ><HR
66 ALIGN="LEFT"
67 WIDTH="100%"></DIV
68 ><DIV
69 CLASS="SECT1"
70 ><H1
71 CLASS="SECT1"
72 ><A
73 NAME="GUIDEBASICSINIT"
74 >Initializing SDL</A
75 ></H1
76 ><P
77 >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
78 HREF="sdlinit.html"
79 ><TT
80 CLASS="FUNCTION"
81 >SDL_Init</TT
82 ></A
83 > (or <A
84 HREF="sdlinitsubsystem.html"
85 ><TT
86 CLASS="FUNCTION"
87 >SDL_InitSubSystem</TT
88 ></A
89 >. <TT
90 CLASS="FUNCTION"
91 >SDL_Init</TT
92 > 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:
93 <PRE
94 CLASS="PROGRAMLISTING"
95 > SDL_Init ( SDL_INIT_VIDEO );</PRE
96 >
97 To initialize the default subsystems, the Video subsystem and the Timers subsystem you would call:
98 <PRE
99 CLASS="PROGRAMLISTING"
100 > SDL_Init ( SDL_INIT_VIDEO | SDL_INIT_TIMER );</PRE
101 ></P
102 ><P
103 ><TT
104 CLASS="FUNCTION"
105 >SDL_Init</TT
106 > is complemented by <A
107 HREF="sdlquit.html"
108 ><TT
109 CLASS="FUNCTION"
110 >SDL_Quit</TT
111 ></A
112 > (and <A
113 HREF="sdlquitsubsystem.html"
114 ><TT
115 CLASS="FUNCTION"
116 >SDL_QuitSubSystem</TT
117 ></A
118 >). <TT
119 CLASS="FUNCTION"
120 >SDL_Quit</TT
121 > shuts down all subsystems, including the default ones. It should always be called before a SDL application exits.</P
122 ><P
123 >With <TT
124 CLASS="FUNCTION"
125 >SDL_Init</TT
126 > and <TT
127 CLASS="FUNCTION"
128 >SDL_Quit</TT
129 > 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
130 CLASS="FUNCTION"
131 >SDL_Init</TT
132 >, 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
133 CLASS="FUNCTION"
134 >SDL_GetError</TT
135 >. Use this often, you can never know too much about an error.</P
136 ><P
137 ><PRE
138 CLASS="PROGRAMLISTING"
139 >#include "SDL.h" /* All SDL App's need this */
140 #include &#60;stdio.h&#62;
141
142 int main() {
143
144 printf("Initializing SDL.\n");
145
146 /* Initialize defaults, Video and Audio */
147 if((SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO)==-1)) {
148 printf("Could not initialize SDL: %s.\n", SDL_GetError());
149 exit(-1);
150 }
151
152 printf("SDL initialized.\n");
153
154 printf("Quiting SDL.\n");
155
156 /* Shutdown all subsystems */
157 SDL_Quit();
158
159 printf("Quiting....\n");
160
161 exit(0);
162 }&#13;</PRE
163 ></P
164 ></DIV
165 ><DIV
166 CLASS="NAVFOOTER"
167 ><HR
168 ALIGN="LEFT"
169 WIDTH="100%"><TABLE
170 WIDTH="100%"
171 BORDER="0"
172 CELLPADDING="0"
173 CELLSPACING="0"
174 ><TR
175 ><TD
176 WIDTH="33%"
177 ALIGN="left"
178 VALIGN="top"
179 ><A
180 HREF="guidethebasics.html"
181 >Prev</A
182 ></TD
183 ><TD
184 WIDTH="34%"
185 ALIGN="center"
186 VALIGN="top"
187 ><A
188 HREF="index.html"
189 >Home</A
190 ></TD
191 ><TD
192 WIDTH="33%"
193 ALIGN="right"
194 VALIGN="top"
195 ><A
196 HREF="guidevideo.html"
197 >Next</A
198 ></TD
199 ></TR
200 ><TR
201 ><TD
202 WIDTH="33%"
203 ALIGN="left"
204 VALIGN="top"
205 >The Basics</TD
206 ><TD
207 WIDTH="34%"
208 ALIGN="center"
209 VALIGN="top"
210 ><A
211 HREF="guidethebasics.html"
212 >Up</A
213 ></TD
214 ><TD
215 WIDTH="33%"
216 ALIGN="right"
217 VALIGN="top"
218 >Graphics and Video</TD
219 ></TR
220 ></TABLE
221 ></DIV
222 ></BODY
223 ></HTML
224 >