Need to call child_process.exec twice for it to work

Question

Need to call child_process.exec twice for it to work

In an node.js application I have the following code that is supposed to start a program called timestamp:

var exec = require('child_process').exec, child;

child = exec('./timestamp 207.99.83.228 5000 -p 5500 &', function (error, stdout, stderr) {
    if (error !== null) {
        console.log('exec error: ' + error);
    } else {
        // Code to be executed after the timestamp program has started
        ...
    }
});

However, this will not start the timestamp program unless I preceed the call to exec by this:

exec('./timestamp 207.99.83.228 5000 -p 5500 &', null);

If I leave out this line, there is nothing, not even an error message.

So, in order to successfully start one instance of the program, I have to call exec twice. Is that some bug in node.js or the ChildProcess class or am I missing something here?

node.js