ignore_handler_s

 

C

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Technical Specifications

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Error handling

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Error codes

errno

Assertions

assert

static_assert (C11)(removed in C23)

Bounds checking

set_constraint_handler_s (C11)

abort_handler_s (C11)

ignore_handler_s (C11)

 

Defined in header <stdlib.h>
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>.

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

Return value

(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

Run this code

#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)

See also

abort_handler_s (C11)	abort callback for the bounds-checked functions (function)
set_constraint_handler_s (C11)	set the error callback for bounds-checked functions (function)