i have been trying to conduct a occlusion query with

function 'glBeginQuery(GL_SAMPLES_PASSED,queryid);'. however,

there is a error that says 'glBeginQuery : undeclared

identifier ' and 'GL_SAMPLES_PASSED: undeclared identifier';

i have included 'gl\gl.h','gl\glu.h' & 'gl\glaux.h'.

Could any buddy do me a favor to solve this problem? thanks!