SIG_DFL, SIG_IGN

#define SIG_DFL /*implementation defined*/

#define SIG_IGN /*implementation defined*/

The SIG_DFL and SIG_IGN macros expand into integral expressions that are not equal to an address of any function. The macros define signal handling strategies for signal() function.

Example

#include <signal.h>
#include <stdio.h>
 
int main(void)
{
    /* using the default signal handler */
    raise(SIGTERM);
    printf("Exit main()\n");   /* never reached */
}

(none)

Example

#include <signal.h>
#include <stdio.h>
 
int main(void)
{
    /* ignoring the signal */
    signal(SIGTERM, SIG_IGN);
    raise(SIGTERM);
    printf("Exit main()\n");
}

Exit main()

References

• C17 standard (ISO/IEC 9899:2018):
• 7.14/3 Signal handling <signal.h> (p: 193)
• C11 standard (ISO/IEC 9899:2011):
• 7.14/3 Signal handling <signal.h> (p: 265)
• C99 standard (ISO/IEC 9899:1999):
• 7.14/3 Signal handling <signal.h> (p: 246)
• C89/C90 standard (ISO/IEC 9899:1990):
• 4.7 SIGNAL HANDLING <signal.h>

See also