strncat.c

标准c库代码,可以应用于各个系统提供了大量的基本函数

/*
FUNCTION
	<<strncat>>---concatenate strings

INDEX
	strncat

ANSI_SYNOPSIS
	#include <string.h>
	char *strncat(char *<[dst]>, const char *<[src]>, size_t <[length]>);

TRAD_SYNOPSIS
	#include <string.h>
	char *strncat(<[dst]>, <[src]>, <[length]>)
	char *<[dst]>;
	char *<[src]>;
	size_t <[length]>;

DESCRIPTION
	<<strncat>> appends not more than <[length]> characters from
	the string pointed to by <[src]> (including the	terminating
	null character) to the end of the string pointed to by
	<[dst]>.  The initial character of <[src]> overwrites the null
	character at the end of <[dst]>.  A terminating null character
	is always appended to the result

WARNINGS
	Note that a null is always appended, so that if the copy is
	limited by the <[length]> argument, the number of characters
	appended to <[dst]> is <<n + 1>>.
	

RETURNS
	This function returns the initial value of <[dst]>

PORTABILITY
<<strncat>> is ANSI C.

<<strncat>> requires no supporting OS subroutines.

QUICKREF
	strncat ansi pure
*/

#include <string.h>

char *
_DEFUN (strncat, (s1, s2, n),
	char *s1 _AND
	_CONST char *s2 _AND
	size_t n)
{
  char *s = s1;

  while (*s1)
    s1++;
  while (n-- != 0 && (*s1++ = *s2++))
    {
      if (n == 0)
	*s1 = '\0';
    }

  return s;
}