glClearStencil — specify the clear value for the stencil buffer
void glClearStencil (GLint s);
Specifies the index used when the stencil buffer is cleared. The initial value is 0.
glClearStencil specifies the index used by glClear to clear the stencil buffer. s is masked with 2m-1, where m is the number of bits in the stencil buffer.
GL_INVALID_OPERATION
is generated if glClearStencil is executed between the execution of glBegin and
the corresponding execution of glEnd.
glGet with argument GL_STENCIL_CLEAR_VALUE
glGet with argument GL_STENCIL_BITS
glClear, glStencilFunc, glStencilFuncSeparate, glStencilMask, glStencilMaskSeparate, glStencilOp, glStencilOpSeparate