Name
gl.GetError -- return error information
Synopsis
error = gl.GetError()
Function
gl.GetError() 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 gl.GetError() is called, the error code is returned, and the flag is reset to #GL_NO_ERROR. If a call to gl.GetError() returns #GL_NO_ERROR, there has been no detectable error since the last call to gl.GetError(), 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 gl.GetError() is called. If more than one flag has recorded an error, gl.GetError() returns and clears an arbitrary error flag value. Thus, gl.GetError() 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.

#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.

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 gl.GetError() itself generates an error, it returns 0.

Please consult an OpenGL reference manual for more information.

Inputs
none

Results
error
value of GL's error flag
Errors
#GL_INVALID_OPERATION is generated if gl.GetError() is executed between the execution of gl.Begin() and the corresponding execution of gl.End() . In this case, gl.GetError() returns 0.

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