C++ Signal Handling

PREV

What is signal handling?

  • Signals are the interrupts which force the operating system to stop the ongoing tasks and attend the task for which the interrupt has been sent.
  • These interrupt can pause a service in any program of an operating system. In C++, various signals are offered which can catch and process in a program.
  • The programmers can generate interrupts by pressing Ctrl+C on a LINUX, UNIX, Windows or Mac OS X. Some of the signals cannot be caught by the program but there is a following list of signals which you can catch in your program and can take proper actions based on the signal.

The <csignal> header file is used to define these signals.


SIGINT:

It produces receipt for an active signal.

SIGABRT:

It terminates the program abnormally.

SIGTERM:

It sends a termination request to the program.

SIGFPE:

It produces the erroneous arithmetic operation such as divide by zero or an operation resulting in an overflow.

SIGSEGV:

It means an invalid access to storage.


SIGILL:

This signal detects the illegal command or instruction.

The signal ( ) Function

In C++, signal handling library provides function signal to trap unexpected events.

Syntax for this function is:

signal(registered signal, signal handler)

  • In the above syntax, the first argument is an integer which represents the signal number and the second argument is the pointer to a signal handling function.
  • The signal which we want to be catching it should be registered and must be associated with a signal handling function. It should be of void type.

Let us have a look at the example:

To interrupt in between the program press Ctrl+C.

The raise( ) Function

In C++, the raise( ) function is used to generate signals. It takes integer signal number as an argument.

Syntax for the following is:

raise(signal sig);

In the above syntax, sig is the signal number which is used to send any of the signals: SIGABRT, SIGINT, SIGTERM, SIGSEGV, SIGILL, SIGHUP, SIGFPE.

Let us have a look at the example:

PREV



Share this website !!!
Facebook Twitter Linkedin