Returns true if stat is successful, false if
not. Returns nil if exited? is not
true.
/*
* call-seq:
* stat.success? => true, false or nil
*
* Returns +true+ if _stat_ is successful, +false+ if not.
* Returns +nil+ if <code>exited?</code> is not +true+.
*/
static VALUE
pst_success_p(st)
VALUE st;
{
int status = NUM2INT(st);
if (!WIFEXITED(status))
return Qnil;
return WEXITSTATUS(status) == EXIT_SUCCESS ? Qtrue : Qfalse;
}