glDepthMask -	enable or disable writing into the depth
buffer

glDepthMask
	glDepthMask(flag) -> None

void glDepthMask( GLboolean flag )

flag	Specifies whether the depth buffer is enabled for
      writing.  If flag is GL_FALSE, depth buffer writing is
      disabled.  Otherwise, it is enabled.  Initially, depth
      buffer writing is enabled.

glDepthMask specifies	whether	the depth buffer is enabled
for writing.	If flag	is GL_FALSE, depth buffer writing is
disabled.  Otherwise,	it is enabled.	Initially, depth
buffer writing is enabled.

GL_INVALID_OPERATION is generated if glDepthMask is executed
between the execution	of glBegin and the corresponding
execution of glEnd.

glGet	with argument GL_DEPTH_WRITEMASK

glColorMask, glDepthFunc, glDepthRange, glIndexMask,
glStencilMask