PHP, How to catch a division by zero?

if ($baz == 0.0) {
    echo 'Divisor is 0';
} else {
    ...
}

Rather than use eval, which is highly dangerous if you're using user-input within the evalled expression, why not use a proper parser such as evalmath on PHPClasses, and which raises a clean exception on divide by zero

You just need to set an error handler to throw an exception in case of errors:

set_error_handler(function () {
    throw new Exception('Ach!');
});

try {
    $result = 4 / 0;
} catch( Exception $e ){
    echo "Divide by zero, I don't fear you!".PHP_EOL;
    $result = 0;
}

restore_error_handler();

On PHP7 you can use DivisionByZeroError

try {
    echo 1/0;
} catch(DivisionByZeroError $e){
    echo "got $e";
} catch(ErrorException $e) {
    echo "got $e";
}

Here's another solution:

<?php

function e($errno, $errstr, $errfile, $errline) {
    print "caught!\n";
}

set_error_handler('e');

eval('echo 1/0;');

See set_error_handler()