C API/Boolean values

C API functions can accept or return boolean values of  or. These can be converted to and from a C program's idea of true and false as follows:


 * To convert a  to a C boolean, use  . This evaluates as false if   is   or , and true otherwise.


 * To convert a C boolean to a, use.

dl.h has a macro  that converts a C boolean to a VALUE; but it is not clear that dl.h is meant to be used in extensions.