C ++-从注册表读取的值中获取空值 [英] C++ - getting null values in value read from registry

问题描述

我的应用程序正确读取和写入注册表.现在，我需要从以下位置读取注册表值:

My application properly reads and writes to the registry. Now, I need to read a registry value from:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\MachineGuid

这是我的代码:

bool GetWindowsID(string &winID)
{
    HKEY hKey = 0, hKeyType = HKEY_LOCAL_MACHINE;
    bool status = false;
    DWORD dwType = 0;
    DWORD dwBufSize = 256;
    char value[256] = "\0";
    if (RegOpenKeyEx(hKeyType, L"SOFTWARE\\Microsoft\\Cryptography", NULL, KEY_QUERY_VALUE|KEY_WOW64_64KEY, &hKey) == ERROR_SUCCESS)
    {
        dwType = REG_SZ;
        if (RegQueryValueEx(hKey, L"MachineGuid", NULL, &dwType, (LPBYTE)value, &dwBufSize) == ERROR_SUCCESS)
            status = true;
        RegCloseKey(hKey);
    }
    winID.assign(value);
    return status;
}

我得到 guid ，但是在每个字符后的 value 数组中，它们是一个"\ 0"值，因为只有数组的第一个字符才分配给字符串.这太奇怪了！

I get the guid but in value array after each character their is a "\0" value due to which only first character of array gets assigned to string. This is wierd!

推荐答案

您已经建立了针对Unicode的代码，因此注册表API返回了UTF-16 Unicode文本.请记住，每个 wchar_t 元素都是2个字节宽，而不是 char .

You have built targeting Unicode and so the registry API is returning UTF-16 Unicode text. Instead of char use wchar_t and remember that each wchar_t element is 2 bytes wide.

还请确保按照文档中的说明，说明返回的字符串不是以空值结尾的.您必须考虑 dwBufSize 中返回的值.

Do also make sure that you account for the returned string not being null-terminated, as described in the documentation. You must take account of the value returned in dwBufSize.

这篇关于C ++-从注册表读取的值中获取空值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！