sig_atomic_t

 

C

Compiler support

Language

Headers

Type support

Program utilities

Variadic function support

Error handling

Dynamic memory management

Strings library

Algorithms

Numerics

Date and time utilities

Input/output support

Localization support

Concurrency support (C11)

Technical Specifications

Symbol index

 

Program support utilities

Program termination
abort exit quick_exit (C11) _Exit (C99)	atexit at_quick_exit (C11) EXIT_SUCCESSEXIT_FAILURE
Unreachable control flow
unreachable (C23)
Communicating with the environment
getenvgetenv_s (C11)	system
Memory alignment query
memalignment (C23)
Signals
signal raise sig_atomic_t	SIG_DFLSIG_IGN SIG_ERR
Signal types
SIGABRTSIGFPESIGILL	SIGINTSIGSEGVSIGTERM
Non-local jumps
setjmp	longjmp
Types
jmp_buf

 

Defined in header <signal.h>
typedef /* unspecified */ sig_atomic_t;

An integer type which can be accessed as an atomic entity even in the presence of asynchronous interrupts made by signals.

Example

Run this code

#include <signal.h>
#include <stdio.h>
 
volatile sig_atomic_t gSignalStatus = 0;
 
void signal_handler(int status)
{
    gSignalStatus = status;
}
 
int main(void)
{
    /* Install a signal handler. */
    signal(SIGINT, signal_handler);
 
    printf("SignalValue:    %d\n", gSignalStatus);
    printf("Sending signal: %d\n", SIGINT);
    raise(SIGINT);
    printf("SignalValue:    %d\n", gSignalStatus);
}

Possible output:

SignalValue:    0
Sending signal: 2
SignalValue:    2

References

• C17 standard (ISO/IEC 9899:2018):

• 7.14/2 Signal handling <signal.h> (p: 194-195)

• C11 standard (ISO/IEC 9899:2011):

• 7.14/2 Signal handling <signal.h> (p: 265)

• C99 standard (ISO/IEC 9899:1999):

• 7.14/2 Signal handling <signal.h> (p: 246)

• C89/C90 standard (ISO/IEC 9899:1990):

• 4.7 SIGNAL HANDLING <signal.h>

See also

signal	sets a signal handler for particular signal (function)
C++ documentation for sig_atomic_t