Declaration

void (*signal(int iSignal, void (*pfnInterrupt) (int [, int ] ))) (int);

Description

This function assigns a handler to a given signal. The first int argument is the signal value and the function pointer pfnInterrupt points to the new handler. A pointer to the old handler is returned.

Signal Macro Table

Macro	Description	Value
SIGINT	Interrupt Ctrl-C	2
SIGILL	Illegal Instruction	4
SIGFPE	Floating-point Exception	8
SIGSEGV	Segment Violation	11
SIGTERM	Termination Request	15
SIGBREAK	Ctrl-Break	21
SIGABRT	Abnormal Termination — Abort	22

Handler Macro Table*

Macro	Description	Value
SIG_ERR	Signal error value	–1
SIG_DFL	Default handler	0
SIG_IGN	Ignore signal	1
SIG_GET	Return the current value	2
SIG_SGE	Signal gets error	3
SIG_ACK	Acknowledge	4

* Note: These macros are replaced by function pointers, some of which may not exist on all platforms. All of these are defined in Visual C++ 2008.

Example

#include <iostream>
#include <csignal>

void InterruptHandler(int iArgument) {
    std::cout << "Inside Handler" << std::endl;
    std::cout << "Handler Argument = " << iArgument << std::endl;
}

int main() {
    using namespace std;

    void (*pfnOldHandler)(int);

    pfnOldHandler       = signal(SIGTERM, InterruptHandler);
    int iReturnValue    = raise(SIGTERM);
    cout << "Return value = " << iReturnValue << endl;

    return 0;
}

Output