C library functions -sigaddset()

C Standard Library - <signal.h>

Description

sigaddsetThe function is a function in the C standard library, used to add a specific signal to a signal set. This function is defined in<signal.h>In the header file.

Syntax

int sigaddset(sigset_t *set, int signo);

Parameter

  • sigset_t *set: points to asigset_tA signal set variable of type.
  • int signo: the signal number to be added to the signal set.

Return Value

  • Returns 0 on success.
  • On failure, returns -1 and setserrnoto indicate the error type.

Example

The following is an example usingsigaddsetAn example program of the function adding a specific signal to a signal set. The program initializes an empty signal set andSIGINTadds the signal to the signal set, and checks whether the signal set containsSIGINTsignal.

Example

#include <stdio.h>
#include <signal.h>

int main() {
    sigset_t set;

    // Initialize the signal set to empty
    if (sigemptyset(&set) == -1) {
        perror("sigemptyset");
        return 1;
    }

    // add SIGINT to the signal set
    if (sigaddset(&set, SIGINT) == -1) {
        perror("sigaddset");
        return 1;
    }

    // Check whether the signal set contains SIGINT
    if (sigismember(&set, SIGINT)) {
        printf("SIGINT is in the set\n");
    } else {
        printf("SIGINT is not in the set\n");
    }

    return 0;
}

The possible output of running the above example program is as follows:

SIGINT is in the set

The program initializes an empty signal set andSIGINTadds the signal to the signal set, and checks whether the signal set containsSIGINTsignal, the results show thatSIGINTthe signal is in the signal set.

Explanation

  • sigset_t set;: Defines a signal set variable.
  • UsagesigemptysetThe function initializes the signal set to empty.
  • UsagesigaddsetThe function willSIGINTAdds the signal to the signal set.
  • UsagesigismemberThe function checks whether the signal set containsSIGINTsignal.
  • The output showsSIGINTthe signal in the initialized signal set.

Notes

  • sigaddsetThe function is used to add a specific signal to a signal set.
  • If the signal number is invalid,sigaddsetthe function will return -1 and seterrnoto indicate the error type.

C Standard Library - <signal.h>

other extensions