glutReportErrors

This routine prints out any OpenGL run-time errors pending and clears the errors. This routine typically should only be used for debugging purposes since calling it will slow OpenGL programs. It is provided as a convenience; all the routine does is call glGetError until no more errors are reported. Any errors detected are reported with a GLUT warning and the corresponding text message generated by gluErrorString .

Calling glutReportErrors repeatedly in your program can help isolate OpenGL errors to the offending OpenGL command. Remember that you can use the -gldebug option to detect OpenGL errors in any GLUT program.