signal

 

C

Language

Standard Library

Type support

Dynamic memory management

Error handling

Program utilities

Date and time utilities

Strings library

Algorithms

Numerics

Input/output support

Localization support

Thread support (C11)

Atomic operations (C11)

 

Program support utilities

Program termination
abort exit quick_exit (C++11) _Exit (C++11)	atexit at_quick_exit (C++11) EXIT_SUCCESSEXIT_FAILURE
Communicating with the environment
system	getenv
Signals
signal raise sig_atomic_t	SIG_DFLSIG_IGN SIG_ERR
Signal types
SIGABRTSIGFPESIGILLSIGINTSIGSEGVSIGTERM
Non-local jumps
setjmp
longjmp
Types
jmp_buf

 

Defined in header <signal.h>
void (*signal( int sig, void (*handler) (int))) (int);

Sets the error handler for signal sig. The signal handler can be set so that default handling will occur, signal is ignored, or an user-defined function is called.

When signal handler is set to a function and a signal occurs, it is implementation defined whether signal(sig, SIG_DFL) will be executed immediately before the start of signal handler. Also, the implementation can prevent some implementation-defined set af signals from occurring while the signal handler runs.

If the user defined function returns when handling SIGFPE, SIGILL or SIGSEGV, the behavior is undefined. In most implementations the program terminates.

If the signal handler is called as a result of abort or raise, the behavior is undefined if any of the following requirements is not followed:

• the signal handler calls raise.
• the signal handler refers to an object of static storage duration which is not declared as volatile sig_atomic_t.
• the signal handler calls any function within the standard library, except abort, _Exit, or signal with the first argument not being the number of the signal currently handled.

Parameters

sig	-	the signal to set the signal handler to. It can be an implementation-defined value or one of the following values: SIGABRTSIGFPESIGILLSIGINTSIGSEGVSIGTERM defines signal types (macro constant)
handler	-	the signal handler. This must be one of the following: SIG_DFL macro. The signal handler is set to default signal handler. SIG_IGN macro. The signal is ignored. pointer to a function. The signature of the function must be equivalent to the following: void fun(int sig);

Return value

Previous signal handler on success or SIG_ERR on failure (setting a signal handler can be disabled on some implementations).

See also

raise	runs the signal handler for particular signal (function)
C++ documentation for signal