glClearColor alpha parameter ?useless?

OpenGL OpenGL: Advanced Coding
1

using glClearColor with the alph parameter set to 0 should have any effect ie. should not clear the screen.

when i use glClearColor(0.0,0.0,0.0, x),
the screen is cleared to black no matter what value the x is. and yes, i do have the blend functions enabled and defined, so with a x = 0.5 i should get a tracer/fade type effect.

anyone know what might be going on?

2

That value is used to clear the alpha buffer if such a buffer is available. It does not affect how the color buffer is cleared.
The alpha buffer is used for destination alpha blending when drawing objects.