gluCheckExtension

gluCheckExtension: man2/gluCheckExtension.xml

gluCheckExtension returns GLU_TRUE if extName is supported otherwise GLU_FALSE is returned. This is used to check for the presence for OpenGL, GLU, or GLX extension names by passing the extension strings returned by glGetString, gluGetString, glXGetClientString, glXQueryExtensionsString, or glXQueryServerString, respectively, as extString.

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.