/ comp / gb.opengl / gl / geterror
Gl.GetError (gb.opengl)
Syntax

    STATIC FUNCTION GetError ( ) AS Integer

### Return error information

#### Description

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.GL_NO_ERROR. If a call to Gl.GetError returns Gl.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.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.GL_NO_ERROR, if all error flags are to be reset.

Initially, all error flags are set to Gl.GL_NO_ERROR.

The currently defined errors are as follows:

- Gl.GL_NO_ERROR no error has been recorded. The value of this symbolic constant is guaranteed to be zero.

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

- Gl.GL_INVALID_VALUE a numeric argument is out of range. The offending command is ignored, having no side effect other than to set the error flag.

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

- Gl.GL_STACK_OVERFLOW this command would cause a stack overflow. The offending command is ignored, having no side effect other than to set the error flag.

- Gl.GL_STACK_UNDERFLOW this command would cause a stack underflow. The offending command is ignored, having no side effect other than to set the error flag.

- Gl.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.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.

#### Errors

Gl.GL_INVALID_OPERATION is generated if Gl.GetError is called between a call to Gl.Begin and the corresponding call to Gl.End.