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 |   <h1>The Mesa 3D Graphics Library</h1> | 
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 |  | 
 | <h1>Debugging Tips</h1> | 
 |  | 
 | <p> | 
 |    Normally Mesa (and OpenGL) records but does not notify the user of | 
 |    errors.  It is up to the application to call | 
 |    <code>glGetError</code> to check for errors.  Mesa supports an | 
 |    environment variable, MESA_DEBUG, to help with debugging.  If | 
 |    MESA_DEBUG is defined, a message will be printed to stdout whenever | 
 |    an error occurs. | 
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 |  | 
 | <p> | 
 |    More extensive error checking is done when Mesa is compiled with the | 
 |    DEBUG symbol defined.  You'll have to edit the Make-config file and | 
 |    add -DDEBUG to the CFLAGS line for your system configuration.  You may | 
 |    also want to replace any optimization flags with the -g flag so you can | 
 |    use your debugger.  After you've edited Make-config type 'make clean' | 
 |    before recompiling. | 
 | </p> | 
 | <p> | 
 |    In your debugger you can set a breakpoint in _mesa_error() to trap Mesa | 
 |    errors. | 
 | </p> | 
 | <p> | 
 |    There is a display list printing/debugging facility.  See the end of | 
 |    src/dlist.c for details. | 
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