The dbx cont command supports the -sig signal option, which lets you resume execution of a program with the program behaving as if it had received the system signal signal.
For example, if a program has an interrupt handler for SIGINT (^C), you can type ^C to stop the application and return control to dbx. If you issue a cont command by itself to continue program execution, the interrupt handler never executes. To execute the interrupt handler, send the signal, SIGINT, to the program:
(dbx) cont -sig int
The step command, next command, and detach command accept -sig as well.