strncpy_s.c File Reference

#include "safe_str_lib.h"

Include dependency graph for strncpy_s.c:

Functions
EXPORT errno_t	strncpy_s (char *restrict dest, rsize_t dmax, const char *restrict src, rsize_t slen)
	The strncpy_s function copies not more than slen successive characters (characters that follow a null character are not copied) from the array pointed to by src to the array pointed to by dest. More...

Function Documentation

strncpy_s()

EXPORT errno_t strncpy_s	(	char *restrict	dest,
		rsize_t	dmax,
		const char *restrict	src,
		rsize_t	slen
	)

The strncpy_s function copies not more than slen successive characters (characters that follow a null character are not copied) from the array pointed to by src to the array pointed to by dest.

If no null character was copied from src, then dest[n] is set to a null character.

All elements following the terminating null character (if any) written by strncpy_s in the array of dmax characters pointed to by dest take unspecified values when strncpy_s returns. With SAFECLIB_STR_NULL_SLACK defined the rest is cleared with NULL bytes.

Remarks

SPECIFIED IN

• C11 standard (ISO/IEC 9899:2011): 7.21.2.4 The strncpy function (p: 326-327) http://en.cppreference.com/w/c/string/byte/strncpy
• ISO/IEC TR 24731-1, Programming languages, environments and system software interfaces, Extensions to the C Library, Part I: Bounds-checking interfaces

Parameters

[out]	dest	pointer to string that will be replaced by src.
[in]	dmax	restricted maximum length of dest
[in]	src	pointer to the string that will be copied to dest
[in]	slen	the maximum number of characters to copy from src

Precondition

Neither dmax nor slen shall be equal to zero.

Neither dmax nor slen shall be equal zero.

Neither dmax nor slen shall be greater than RSIZE_MAX_STR.

If slen is either greater than or equal to dmax, then dmax should be more than strnlen_s(src,dmax) to avoid truncation.

Copying shall not take place between objects that overlap.

Note

C11 uses RSIZE_MAX, not RSIZE_MAX_STR.

Returns

If there is a runtime-constraint violation, then if dest is not a null pointer and dmax greater than RSIZE_MAX_STR, then strncpy_s nulls dest.

Return values

EOK	successful operation, the characters in src were copied to dest and the result is null terminated.
ESNULLP	when dest/src is NULL pointer
ESZEROL	when dmax/slen = 0
ESLEMAX	when dmax/slen > RSIZE_MAX_STR
ESOVRLP	when strings overlap
ESNOSPC	when dest < src

See also

strcat_s(), strncat_s(), strcpy_s(), wcsncpy_s()