void is a return-only type declaration indicating the function does not return a value, but the function may still terminate. Therefore, it cannot be part of a union type declaration. Available as of PHP 7.1.0.
Note: Even if a function has a return type of void it will still return a value, this value is always
null.
(void)
The (void) syntax may be used to explicitly discard the
result of an expression. This is useful to indicate that ignoring a return
value is intentional, especially when calling a function or method marked
with the NoDiscard
attribute.
Unlike other casts, (void) does not convert the value to
another type and does not produce a value. It is a statement and cannot be
used as part of an expression.
Example #1 Discarding a return value
<?php
#[\NoDiscard]
function process(): bool {
return true;
}
(void) process(); // Explicitly discard the return value
?>