sig_atomic_t

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

#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);
}

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