Defined in header <signal.h> | ||
---|---|---|
#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.
Constant | Explanation |
---|---|
SIG_DFL | default signal handling |
SIG_IGN | signal is ignored |
Example
#include <signal.h> #include <stdio.h> int main(void) { /* using the default signal handler */ raise(SIGTERM); printf("Exit main()\n"); /* never reached */ }
Output:
(none)
Example
#include <signal.h> #include <stdio.h> int main(void) { /* ignoring the signal */ signal(SIGTERM, SIG_IGN); raise(SIGTERM); printf("Exit main()\n"); }
Output:
Exit main()
References
- 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
C++ documentation for SIG_DFL, SIG_IGN |
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