为什么RegOpenKeyEx()和RegQueryValueEx()中的相同路径不起作用? [英] Why same path in RegOpenKeyEx() and RegQueryValueEx() is not working?

问题描述

大家好，

我尝试从注册表中读取一个值，请尝试以下代码
注意
:基于Windows7
:使用MSVC ++ 2010作为工具

Hello everyone,

I try to read a value from registry, I try this code
Note
: based on Windows7
: using MSVC++2010 as tool

#include <windows.h>
#include <malloc.h>
#include <stdio.h>

#define TOTALBYTES    8192


void main()
{
    DWORD BufferSize = TOTALBYTES;
    DWORD cbData;
    DWORD dwRet;
	HKEY result;

    PPERF_DATA_BLOCK PerfData = (PPERF_DATA_BLOCK) malloc( BufferSize );

	dwRet = RegOpenKeyEx(HKEY_LOCAL_MACHINE,
							TEXT("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0\\"),
							0,
							KEY_ALL_ACCESS,
							&result
		);
    if( dwRet == ERROR_SUCCESS )
        printf("\n\RegOpenKeyEx result : %d, function successed\n", &result);
    else printf("\nRegOpenKeyEx failed (%d)\n", dwRet);
	
	dwRet = RegQueryValueEx( HKEY_LOCAL_MACHINE,
                             TEXT("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0\\~MHz"),
                             NULL,
                             NULL,
                             (LPBYTE) PerfData,
                             &cbData );
	if( dwRet == ERROR_SUCCESS )
        printf("\n\nRegQueryValueEx result(~MHz) %d, function successed\n", &cbData);
    else printf("\nRegQueryValueEx(~MHz) failed (%d)\n", dwRet);

	dwRet = RegQueryValueEx( HKEY_LOCAL_MACHINE,
                             TEXT("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0"),
                             NULL,
                             NULL,
                             (LPBYTE) PerfData,
                             &cbData);
	if( dwRet == ERROR_SUCCESS )
        printf("\n\nRegQueryValueEx result %d, function successed\n", &cbData);
    else printf("\nRegQueryValueEx failed (%d)\n", dwRet);

	dwRet = RegCloseKey(result);
	if( dwRet == ERROR_SUCCESS )
        printf("\n\nRegCloseKey successed\n");
    else printf("\nRegCloseKey failed (%d)\n", dwRet);


	system("pause");
}

为什么RegQueryValueEx()中的两个路径不起作用，因为它们在RegOpenKeyEx()和RegCloseKey()上起作用?

Why two paths in RegQueryValueEx() is not working, as it works on RegOpenKeyEx() and RegCloseKey()?

推荐答案

因为，正如Jochen Arndt已经提到的，RegQueryValueEx不能那样工作:您误解了功能文档.更改，例如

Because, as already noted by Jochen Arndt, RegQueryValueEx does NOT work that way: you misunderstood the function documentation. Change, for instance

windyl3ig写道:

windyl3ig wrote:

dwRet = RegQueryValueEx( HKEY_LOCAL_MACHINE,
                             TEXT("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0\\~MHz"),
                             NULL,
                             NULL,
                             (LPBYTE) PerfData,
                             &cbData );

到

to

DWORD dwMHz;
cbData = sizeof(dwMHz);
dwRet = RegQueryValueEx( result,
                         TEXT("~MHz"),
                         NULL,
                         NULL,
                         (LPBYTE) &dwMHz,
                         &cbData );

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