This is used to check for the presence for OpenGL, GLU or GLX extension names by passing the extensions strings returned by glGetString , gluGetString , or glXGetClientString , respectively, as extString . Parameters extName Specifies an extension name. Notes Cases where one extension name is a substring of another are correctly handled. There may or may not be leading or trailing blanks in extString . Extension names should not contain embedded spaces.
All strings are null-terminated.
The glGetString subroutine, gluGetString subroutine, glXGetClientString subroutine.