Actually you were right, it is WinExec!
If you run control.exe from this function you can make any of the control panel windows show up (fonts, printers, etc.)
So the barebones command-line program to make the clock dialog pop-up would be:
#include <windows.h>
int main()
{
WinExec("control.exe date/time", SW_NORMAL);
return 0;
}
--Will Duty
wduty@radicalfringe.com