what value will be passed when i press the key a

Question

When I press Ctrl+c then SIGINT will be passed to signal() . What value will be pass to the system call signal() when i press a key A ?

Answer 1

No signal will be raised.

The purpose of signals is to inform about a special condition outside normal program flow. Processing input, like the letter A, is part of normal program flow. These two are completely separate, and have different goals.

If you're on UNIX, type man signal on your console.