When a signal (like os.Interrupt) is sent to a process, does the process waits until finish the process? Or, do we have to wait some time after?
I think you are asking if sending a signal will wait till the process is finished?
The answer is that it depends on the platform and the type of signal you send and what the process does with the signal. Some signals such as Kill can't be caught and will cause the process to terminate. Others don't do anything unless the process handles them. Still others will do something if the process doesn't handle them but the process can handle it if it want's to do something different. Until I know more about what you are asking this is the best answer I can give.
You have to wait a moment (or a long time, maybe even forever, depending on how the signal is being handled).