0 (Zero) on a GeForce4-Ti4200. If I'm not mistaken you have to set some flags to make sure a stencil buffer is created. Look up the bglCreateContext command to see the different flags.
Using:
Using:
bglCreateContext(800,600,0,0,BGL_BACKBUFFER|BGL_DEPTHBUFFER|BGL_STENCILBUFFER)I get 8 stencil bits.