# glGetError

Definition: | include pGUI.e include opengl.e integer res = glGetError()
Description: | The glGetError function returns one of the following error codes, as defined in opengl.e:
                                            --  Hex     Decimal
    global constant GL_NO_ERROR             = #0000,    --    0 -- No error has been recorded.
                    GL_INVALID_ENUM         = #0500,    -- 1280 -- Unacceptable value specified for an enumerated argument.
                    GL_INVALID_VALUE        = #0501,    -- 1281 -- A numeric argument is out of range.
                    GL_INVALID_OPERATION    = #0502,    -- 1282 -- Specified operation not allowed in the current state.
                    GL_STACK_OVERFLOW       = #0503,    -- 1283 -- This function would cause a stack overflow.
                    GL_STACK_UNDERFLOW      = #0504,    -- 1284 -- This function would cause a stack underflow.
                    GL_OUT_OF_MEMORY        = #0505     -- 1285 -- There is not enough memory left to execute the function.
                                                                -- The state of OpenGL is undefined, except for the state
                                                                --  of the error flags, after this error is recorded.
The GL_INVALID_OPERATION error code is returned if any function other than
                glCallList,   glColor,     glEvalCoord,  glIndex,     glNormal,   glVertex
                glCallLists,  glEdgeFlag,  glEvalPoint,  glMaterial,  glTexCoord
was called between glBegin() and the corresponding glEnd(). In my tests I have found that it is safe to call glGetError() between such calls, but it is likely that is a sensible but specific implementation detail, rather than a formal OpenGL specification, and on some systems you may need to defer the call until after the glEnd(). The same error is also returned if glEnd() was called before the corresponding glBegin() was called, or glBegin() was called within a glBegin/glEnd() sequence.
pwa/p2js: | Supported.
Remarks | 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 OpenGL 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. If all error flags are to be reset, you should always call glGetError in a loop until it returns GL_NO_ERROR. Initially, all error flags are set to GL_NO_ERROR. When an error flag is set, results of an OpenGL operation are undefined only if GL_OUT_OF_MEMORY has occurred. In all other cases, the function generating the error is ignored and has no effect on the OpenGL state or framebuffer contents.
See Also: | glBegin, glEnd