Signal is a notification, a message sent by either operating system or some application to our program. Signals are a mechanism for one-way asynchronous notifications. A signal may be sent from the kernel to a process, from a process to another process, or from a process to itself. Signal typically alert a process to some event, such as a segmentation fault, or the user pressing Ctrl-C.

• int - Terminal interrupt.
• quit - Terminal quit.
• term - Termination.
• kill - Kill(can't be caught or ignored).
• cont - Continue executing, if stopped.
• stop - Stop executing(can't be caught or ignored).
• hup - Hangup.
• usr1 - User defined signal 1.
• usr2 - User defined signal 2.

enum Efl.Exe_Signal {
    int: 0,
    quit,
    term,
    kill,
    cont,
    stop,
    hup,
    usr1,
    usr2
}

typedef enum {
    EFL_EXE_SIGNAL_INT = 0,
    EFL_EXE_SIGNAL_QUIT,
    EFL_EXE_SIGNAL_TERM,
    EFL_EXE_SIGNAL_KILL,
    EFL_EXE_SIGNAL_CONT,
    EFL_EXE_SIGNAL_STOP,
    EFL_EXE_SIGNAL_HUP,
    EFL_EXE_SIGNAL_USR1,
    EFL_EXE_SIGNAL_USR2
} Efl_Exe_Signal;