foreach (range(1,10) as $value) {
    // do something
}

function foo() {
    global $counter;
    $counter++;
    return range(1, 10);
}

$counter = 0;
foreach (foo() as $key => $value) {}
printf("The function was executed %d time(s)n", $counter);

$counter = 0;
$result = foo();
foreach ($result as $key => $value) {}
printf("The function was executed %d time(s)n", $counter);

function getrange()
{
    error_log("running getrange()");
    return range(1,10);
}

foreach(getrange() as $val)
{
    ...
}