MEMSET_S(3)						   BSD Library Functions Manual 					       MEMSET_S(3)

NAME

     memset_s -- copy a value to all bytes of a memory buffer

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #define __STDC_WANT_LIB_EXT1__ 1
     #include <string.h>

     errno_t
     memset_s(void *s, rsize_t smax, int c, rsize_t n);

DESCRIPTION

     The memset_s() function copies the value c (converted to an unsigned char) into each of the first n bytes of the memory buffer whose starting
     address is given by s.

     It is a runtime-constraints violation if s is a null pointer, or if either of smax or n is larger than RSIZE_MAX, or if smax is smaller than
     n.  If there is a runtime-constraints violation, and if s is not a null pointer, and if smax is not larger than RSIZE_MAX, then, before
     reporting the runtime-constraints violation, memset_s() copies smax bytes to the destination.

     In contrast to the memset(3) function, calls to memset_s() will never be ``optimised away'' by a compiler.  This property is required by the
     following sentences in section K.3.7.4.1 of ISO/IEC 9899:2011 (``ISO C11''):

	   Unlike  memset(),  any  call  to  the memset_s() function shall be evaluated strictly according to the rules of the abstract machine as
	   described in (5.1.2.3).  That is, any call to the memset_s() function shall assume that the memory indicated by s and n may be accessi-
	   ble in the future and thus must contain the values indicated by c.

RETURN VALUES

     The memset_s() function returns zero for success, or a non-zero error code if there was a runtime-constraints violation.

ERRORS

     memset_s() returns the following error codes.  It does not store the error code in the global errno variable:

     [EINVAL]		The s argument was a null pointer.

     [E2BIG]		One or both of smax or n was larger than RSIZE_MAX.

     [EOVERFLOW]	n was larger than smax.

SEE ALSO

     memset(3).

STANDARDS

     The memset_s() function conforms to ISO/IEC 9899:2011 (``ISO C11''), except that the set_constraint_handler_s() interface is not supported.

BSD
								 February 21, 2012							       BSD