glGetError(3G)		       OpenGL Reference			glGetError(3G)

NAME    [Toc]    [Back]

     glGetError	- return error information

C SPECIFICATION    [Toc]    [Back]

     GLenum glGetError(	void )

DESCRIPTION    [Toc]    [Back]

     glGetError	returns	the value of the error flag.  Each detectable error is
     assigned a	numeric	code and symbolic name.	 When an error occurs, the
     error flag	is set to the appropriate error	code value.  No	other errors
     are recorded until	glGetError is called, the error	code is	returned, and
     the flag is reset to GL_NO_ERROR.	If a call to glGetError	returns
     GL_NO_ERROR, there	has been no detectable error since the last call to
     glGetError, or since the GL was initialized.

     To	allow for distributed implementations, there may be several error
     flags.  If	any single error flag has recorded an error, the value of that
     flag is returned and that flag is reset to	GL_NO_ERROR when glGetError is
     called.  If more than one flag has	recorded an error, glGetError returns
     and clears	an arbitrary error flag	value.	Thus, glGetError should	always
     be	called in a loop, until	it returns GL_NO_ERROR,	if all error flags are
     to	be reset.

     Initially,	all error flags	are set	to GL_NO_ERROR.

     The following errors are currently	defined:

     GL_NO_ERROR		   No error has	been recorded.	The value of
				   this	symbolic constant is guaranteed	to be
				   0.

     GL_INVALID_ENUM		   An unacceptable value is specified for an
				   enumerated argument.	 The offending command
				   is ignored, and has no other	side effect
				   than	to set the error flag.

     GL_INVALID_VALUE		   A numeric argument is out of	range.	The
				   offending command is	ignored, and has no
				   other side effect than to set the error
				   flag.

     GL_INVALID_OPERATION	   The specified operation is not allowed in
				   the current state.  The offending command
				   is ignored, and has no other	side effect
				   than	to set the error flag.

     GL_STACK_OVERFLOW		   This	command	would cause a stack overflow.
				   The offending command is ignored, and has
				   no other side effect	than to	set the	error
				   flag.



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glGetError(3G)		       OpenGL Reference			glGetError(3G)



     GL_STACK_UNDERFLOW		   This	command	would cause a stack underflow.
				   The offending command is ignored, and has
				   no other side effect	than to	set the	error
				   flag.

     GL_OUT_OF_MEMORY		   There is not	enough memory left to execute
				   the command.	 The state of the GL is
				   undefined, except for the state of the
				   error flags,	after this error is recorded.

     GL_TABLE_TOO_LARGE		   The specified table exceeds the
				   implementation's maximum supported table
				   size.  The offending	command	is ignored,
				   and has no other side effect	than to	set
				   the error flag.

     When an error flag	is set,	results	of a GL	operation are undefined	only
     if	GL_OUT_OF_MEMORY has occurred.	In all other cases, the	command
     generating	the error is ignored and has no	effect on the GL state or
     frame buffer contents.  If	the generating command returns a value,	it
     returns 0.	If glGetError itself generates an error, it returns 0.

NOTES    [Toc]    [Back]

     GL_TABLE_TOO_LARGE	was introduced in GL version 1.2.

ERRORS    [Toc]    [Back]

     GL_INVALID_OPERATION is generated if glGetError is	executed between the
     execution of glBegin and the corresponding	execution of glEnd.  In	this
     case glGetError returns 0.


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