(PECL runkit >= 0.8.0)
runkit_return_value_used — Determines if the current functions return value will be used
Returns TRUE if the function's return value is used by the calling scope,
otherwise FALSE
Exemplo #1 runkit_return_value_used() example
<?php
function foo() {
var_dump(runkit_return_value_used());
}
foo();
$f = foo();
?>
O exemplo acima irá imprimir:
bool(false) bool(true)