pub type Tcl_FSGetCwdProc = Option<unsafe extern "C" fn(interp: *mut Tcl_Interp) -> *mut Tcl_Obj>;
pub enum Tcl_FSGetCwdProc { None, Some(unsafe extern "C" fn(*mut Tcl_Interp) -> *mut Tcl_Obj), }
No value.
Some value of type T.
T