2. EL 6 ELS
  3. mesa-libGL-devel
  4. glGetError(3gl)

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GLGETERROR(3G) GLGETERROR(3G)

NAME

glGetError - return error information

C SPECIFICATION

GLenum glGetError( void )









DESCRIPTION


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:



  

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

  

  
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.

  

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

  

  
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.

  

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

  

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

  

  
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.

  

  
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


GL_TABLE_TOO_LARGE was introduced in GL version 1.2.






ERRORS


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.