Method and apparatus for handling asynchronous signals while emulating system calls

The invention determines whether any asynchronous signals are pending and then delivers any such pending signals to the emulated application before the control is transferred to the operating system. A first mechanism sets a global flag, and checks to determine if any signals are pending. If there are pending signals, the emulator halts the emulation of the system call, and delivers the signal to the emulated application. A second mechanism handles signals that arrive after the first mechanism has performed its check. This mechanism checks to see if the global flag is set when a signal arrives. If the flag is set, then the signal is delivered immediately. If the flag is not set, then the signal is deferred. A third mechanism establishes a watch state at the beginning of the emulation, which would be changed by any action of the operating system. When a signal comes in, the emulator checks the watch state. If it does not exist, then the emulator defers the system call.