strncpy.c

来自「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」· C语言 代码 · 共 66 行

/*
FUNCTION
	<<strncpy>>---counted copy string

INDEX
	strncpy

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

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

DESCRIPTION
	<<strncpy>> copies not more than <[length]> characters from the
	the string pointed to by <[src]> (including the terminating
	null character) to the array pointed to by <[dst]>.  If the
	string pointed to by <[src]> is shorter than <[length]>
	characters, null characters are appended to the destination
	array until a total of <[length]> characters have been
	written.

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

PORTABILITY
<<strncpy>> is ANSI C.

<<strncpy>> requires no supporting OS subroutines.

QUICKREF
	strncpy ansi pure
*/

#include <string.h>

char *
_DEFUN (strncpy, (dst, src, n),
	char *dst _AND
	_CONST char *src _AND
	size_t n)
{
  char *dscan;
  _CONST char *sscan;
  size_t count;

  dscan = dst;
  sscan = src;
  count = n;
  while (count > 0)
    {
      --count;
      if ((*dscan++ = *sscan++) == '\0')
	break;
    }
  while (count-- > 0)
    *dscan++ = '\0';

  return dst;
}