Function screen_get_pen 

pub unsafe extern "C" fn screen_get_pen() -> u32

Get the current pen color.

This function uses the following values of errno when an error state is reached: EACCESS - Another resource is currently trying to access the screen mutex.

\return The current pen color in the form of a value from the enum defined in colors.h, or PROS_ERR if there was an error taking or returning the screen mutex.