C++ In a Nutshell

<csignal>

The <csignal> header is the C++ version of the standard C <signal.h> header. It declares functions and macros related to signal handling.

A signal is a condition that can arise during program execution. A signal can originate by an explicit call to raise or abort, from external sources (such as the user interrupting the program), or from internal events (such as floating-point errors or memory violations). Each signal has a handler, which is a function that the C++ library calls when a signal occurs (called raising the signal).

Signals are identified by integers. A program can establish different handlers for different signal numbers. You can choose to ignore a signal by using SIG_IGN as the signal handler. If the signal is raised, no handler is called, and the program continues. Each signal also has a default handler (SIG_DFL). When a program starts, every signal number is initialized with SIG_IGN or SIG_DFL. The details are implementation-defined.

You can set your own handler for any signal by calling the signal function. A handler is a function that takes one parameter: the signal number. The signal handler function is limited in what it can do. Unless a signal is raised by an explicit call to raise or abort, the only useful thing the handler can do is to set a global flag. The type of the flag must be sig_atomic_t.

The standard defines a basic set of signals, and an implementation ...