strdup.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

// 
//  Visopsys
//  Copyright (C) 1998-2007 J. Andrew McLaughlin
//  
//  This library is free software; you can redistribute it and/or modify it
//  under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation; either version 2.1 of the License, or (at
//  your option) any later version.
//
//  This library is distributed in the hope that it will be useful, but
//  WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
//  General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public License
//  along with this library; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//  strdup.c
//

// This is the standard "strdup" function, as found in standard C libraries

#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/api.h>


char *strdup(const char *srcString)
{
  // I don't like this function.  Anyway, it makes a copy of the string.

  int length = 0;
  char *destString = NULL;

  // Check params
  if (srcString == NULL)
    {
      errno = ERR_NULLPARAMETER;
      return (destString = NULL);
    }

  if (visopsys_in_kernel)
    return (destString = NULL);

  length = strlen(srcString);

  destString = malloc(length + 1);
  if (destString == NULL)
    {
      errno = ERR_MEMORY;
      return (destString = NULL);
    }

  strncpy(destString, srcString, length);

  // Return success
  return (destString);
}