RegQueryValueEx, 返回2， windows

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

#define TOTALBYTES    8192
#define BYTEINCREMENT 4096

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

    PPERF_DATA_BLOCK PerfData = (PPERF_DATA_BLOCK) malloc( BufferSize );
    cbData = BufferSize;

    printf("\nRetrieving the data...");

    dwRet = RegQueryValueEx( HKEY_LOCAL_MACHINE,
        TEXT("version"),
        //TEXT("software\\microsoft\\version"),错误，需要先打开"software\\microsoft,再查询键version"的值
        NULL,
        NULL,
        (LPBYTE) PerfData,
        &cbData );

    if( dwRet == ERROR_SUCCESS )
        printf("\n\nFinal buffer size is %d, %s\n", BufferSize, PerfData);
    else printf("\nRegQueryValueEx failed (%d)\n", dwRet);
}