fscanf_s 在 Winserver2008 VS2013 64bit 中无法正常工作

Question

当我们在Visual Studio 2013（C++控制台应用程序）、Os-Winsever2008（64位）中使用fscanf_s方法时，文件指针会提前一到两个字节读取数据。 例如：读取文本文件时，文件的第二行是“Administrator”，但 fscanf_s() 返回单词为“dministrator”。 请帮我纠正这个问题。 该代码在使用 Visual Studio 2008 的 32 位 Windows XP 上运行良好。

FILE* pFile;
pFile = NULL;
string strFile = "E:\\10_Products.lrf";
fopen_s(&pFile, strFile.c_str(), "r");
char szTemp[256];
string strTemp = "";
if (NULL != pFile)
{   
    while (!feof(pFile))
    {
        nRet = fscanf_s(pFile, "%s", szTemp);
        if (EOF == nRet)
        {
            cout << "EOF detected";
        }
    }
    return 0;
}

10_Products.lrf文件的格式如下。

[OPERATOR_LEVEL]
Administrator

Answer 1

来自 fscanf_s() 上的文档，http://msdn.microsoft.com/en-us/library/6ybhk9kc.aspx：

The main difference between the secure functions (with the _s suffix) and the older functions is that the secure functions require the size of each c, C, s, S and [ type field to be passed as an argument immediately following the variable. For more information, see scanf_s, _scanf_s_l, wscanf_s, _wscanf_s_l and scanf Width Specification.

还有http://msdn.microsoft.com/en-us/library/w40768et.aspx：

Unlike scanf and wscanf, scanf_s and wscanf_s require the buffer size to be specified for all input parameters of type c, C, s, S, or [. The buffer size is passed as an additional parameter immediately following the pointer to the buffer or variable. For example, if reading a string, the buffer size for that string is passed as follows:

char s[10];

scanf("%9s", s, 10);

所以你应该这样称呼它：

fscanf_s(fp,"%80s",cmd, sizeof(cmd));