# ignore_handler_s

< c‎ | error

Error handling
 Error codes Error codes errno Assertions assert static_assert(C11)(removed in C23) Bounds checking abort_handler_s(C11) ignore_handler_s(C11)

 Defined in header  void ignore_handler_s( const char * restrict msg,                        void * restrict ptr,                        errno_t error                      ); (since C11)

The function simply returns to the caller without performing any other action.

A pointer to this function can be passed to set_constraint_handler_s to establish a runtime constraints violation handler that does nothing.

As with all bounds-checked functions, ignore_handler_s is only guaranteed to be available if __STDC_LIB_EXT1__ is defined by the implementation and if the user defines __STDC_WANT_LIB_EXT1__ to the integer constant 1 before including <stdlib.h>.

## Contents

### Parameters

 msg - pointer to character string that describes the error ptr - pointer to an implementation-defined object or a null pointer. Examples of implementation-defined objects are objects that give the name of the function that detected the violation and the line number when the violation was detected error - the error about to be returned by the calling function, if it happens to be one of the functions that return errno_t

(none)

### Notes

If ignore_handler_s is used as a the runtime constraints handler, the violations may be detected by examining the results of the bounds-checked function calls, which may be different for different functions (non-zero errno_t, null character written to the first byte of the output string, etc)

If set_constraint_handler_s is never called, the default handler is implementation-defined: it may be abort_handler_s, ignore_handler_s, or some other implementation-defined handler.

### Example

#define __STDC_WANT_LIB_EXT1__ 1
#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int main(void)
{
#ifdef __STDC_LIB_EXT1__
char dst[2];
set_constraint_handler_s(ignore_handler_s);
int r = strcpy_s(dst, sizeof dst, "Too long!");
printf("dst = \"%s\", r = %d\n", dst, r);
set_constraint_handler_s(abort_handler_s);
r = strcpy_s(dst, sizeof dst, "Too long!");
printf("dst = \"%s\", r = %d\n", dst, r);
#endif
}

Possible output:

dst = "", r = 22
abort_handler_s was called in response to a runtime-constraint violation.

The runtime-constraint violation was caused by the following expression in strcpy_s:
(s1max <= (s2_len=strnlen_s(s2, s1max)) ) (in string_s.c:62)

Note to end users: This program was terminated as a result
of a bug present in the software. Please reach out to your
software's vendor to get more help.
Aborted

### References

• C11 standard (ISO/IEC 9899:2011):
• K.3.6.1.3 The ignore_handler_s function (p: 606)