NAME
	  fglStencilMask - control the writing of individual bits in
	  the stencil planes


     FORTRAN SPECIFICATION
	  SUBROUTINE fglStencilMask( INTEGER*4 mask )


     PARAMETERS
	  mask	Specifies a bit	mask to	enable and disable writing of
		individual bits	in the stencil planes.	Initially, the
		mask is	all 1's.

     DESCRIPTION
	  fglStencilMask controls the writing of individual bits in
	  the stencil planes.  The least significant n bits of mask,
	  where	n is the number	of bits	in the stencil buffer, specify
	  a mask.  Where a 1 appears in	the mask, it's possible	to
	  write	to the corresponding bit in the	stencil	buffer.	 Where
	  a 0 appears, the corresponding bit is	write-protected.
	  Initially, all bits are enabled for writing.

     ERRORS
	  GL_INVALID_OPERATION is generated if fglStencilMask is
	  executed between the execution of fglBegin and the
	  corresponding	execution of fglEnd.

     ASSOCIATED	GETS
	  fglGet with argument GL_STENCIL_WRITEMASK
	  fglGet with argument GL_STENCIL_BITS

     SEE ALSO
	  fglColorMask,	fglDepthMask, fglIndexMask, fglStencilFunc,
	  fglStencilOp