Create an arglist for _beginthread function

For the beginthread function in the process library for c on windows, I am able to specify an argument list for the function I wish to call when starting the thread.  However, I can get this to work fine when there is one parameter and I pass in, say an int, just this one.  But what happens if I need to pass the function more than one parameter, e.g. an int and a char*?
I have tried to send the function a string containing the variable names created with sprintf, but when debugging the thread that has been called, the parameter values are all nonsense.