Unrelated issues at least.
add_constant("buh",17);
Compiler Warning: 1: Returning a void expression. Converted to zero. (1) Result: 0
buh;
(2) Result: 17
all_constants()->buh;
(3) Result: 17
sleep(1);
Compiler Warning: 1: Returning a void expression. Converted to zero. (4) Result: 0