newlib-cygwin/newlib/libc/string/strnlen.c

50 lines
873 B
C

/*
FUNCTION
<<strnlen>>---character string length
INDEX
strnlen
ANSI_SYNOPSIS
#include <string.h>
size_t strnlen(const char *<[str]>, size_t <[n]>);
TRAD_SYNOPSIS
#include <string.h>
size_t strnlen(<[str]>, <[n]>)
char *<[src]>;
size_t <[n]>;
DESCRIPTION
The <<strnlen>> function works out the length of the string
starting at <<*<[str]>>> by counting chararacters until it
reaches a NUL character or the maximum: <[n]> number of
characters have been inspected.
RETURNS
<<strnlen>> returns the character count or <[n]>.
PORTABILITY
<<strnlen>> is a GNU extension.
<<strnlen>> requires no supporting OS subroutines.
*/
#undef __STRICT_ANSI__
#include <_ansi.h>
#include <string.h>
size_t
_DEFUN (strnlen, (str, n),
_CONST char *str _AND
size_t n)
{
_CONST char *start = str;
while (*str && n-- > 0)
str++;
return str - start;
}