Defined in header `<signal.h>`
#define SIG_ERR /* implementation defined */

A value of type void (*)(int). When returned by signal, indicates that an error has occurred.

Example

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
 
void signal_handler(int sig)
{
    printf("Received signal: %d\n", sig);
}
 
int main(void)
{
    /* Install a signal handler. */
    if (signal(SIGTERM, signal_handler) == SIG_ERR)
    {
        printf("Error while installing a signal handler.\n");
        exit(EXIT_FAILURE);
    }
 
    printf("Sending signal: %d\n", SIGTERM);
    if (raise(SIGTERM) != 0)
    {
        printf("Error while raising the SIGTERM signal.\n");
        exit(EXIT_FAILURE);
    }
 
    printf("Exit main()\n");
    return EXIT_SUCCESS;
}

Output:

Sending signal: 15
Received signal: 15
Exit main()

References

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

SIG_ERR

Example

References

See also