When i have a EGL setup with double buffer mode, then if i create a pbuffer surface will it also have front buffer and the back buffer like we have in case of window surface.

In case of window surface, we know that we write in the back buffer of window surface and whatever content is present in front buffer, is shown on to the display.

But pbuffer contents are never shown on display.So, can any one please tell me what is the use of front buffer in case of pbuffer here?