How to create a process on Mac OS using fork() and exec()

I am working on a relatively simple, independent "process starter" that I would like to get to work on Windows (XP, Vista, 7), Linux (Ubuntu 10.10) and especially Mac OS X (10.6). Linux and Windows basically work, but I'm having some trouble with the Mac version. I was hoping fork() and exec() functions would work the same way under Mac OS as they work in Linux. So my first question is:

1. Should I use these to create a process on the Mac or are there any platform specific functions to be used?

My current code (which worked fine under Linux) to debug this looks something like this:

pid_t processId = 0;
if (processId = fork()) == 0)
{
    const char * tmpApplication = "/Path/to/TestApplication";

    int argc = 1;
    char * argv[argc + 1];

    argv[0] = tmpApplication;
    argv[1] = NULL;

    execv(tmpApplication, argv);
}else
{
    //[...]
}

Any idea if this could work under Mac OS X as well, because my child process is simply not being launched, while there are no errors that would come up.

Thank you!