C++之NetUserEnum

#ifndef UNICODE
#define UNICODE
#endif
#pragma comment(lib, "netapi32.lib")

#include <stdio.h>
#include <assert.h>
#include <windows.h> 
#include <lm.h>

int wmain(int argc, wchar_t* argv[])
{
    LPUSER_INFO_0 pBuf = NULL;
    LPUSER_INFO_0 pTmpBuf;
    DWORD dwLevel = 0;
    DWORD dwPrefMaxLen = MAX_PREFERRED_LENGTH;
    DWORD dwEntriesRead = 0;
    DWORD dwTotalEntries = 0;
    DWORD dwResumeHandle = 0;
    DWORD i;
    DWORD dwTotalCount = 0;
    NET_API_STATUS nStatus;
    LPTSTR pszServerName = NULL;

    if (argc > 2)
    {
        fwprintf(stderr, L"Usage: %s [\\\\ServerName]\n", argv[0]);
        exit(1);
    }
    // The server is not the default local computer.
    //
    if (argc == 2)
        pszServerName = (LPTSTR)argv[1];
    wprintf(L"\nUser account on %s: \n", pszServerName);
    //
    // Call the NetUserEnum function, specifying level 0; 
    //   enumerate global user account types only.
    //
    do // begin do
    {
        nStatus = NetUserEnum((LPCWSTR)pszServerName,
            dwLevel,
            FILTER_NORMAL_ACCOUNT, // global users
            (LPBYTE*)&pBuf,
            dwPrefMaxLen,
            &dwEntriesRead,
            &dwTotalEntries,
            &dwResumeHandle);
        //
        // If the call succeeds,
        //
        if ((nStatus == NERR_Success) || (nStatus == ERROR_MORE_DATA))
        {
            if ((pTmpBuf = pBuf) != NULL)
            {
                //
                // Loop through the entries.
                //
                for (i = 0; (i < dwEntriesRead); i++)
                {
                    assert(pTmpBuf != NULL);

                    if (pTmpBuf == NULL)
                    {
                        fprintf(stderr, "An access violation has occurred\n");
                        break;
                    }
                    //
                    //  Print the name of the user account.
                    //
                    wprintf(L"\t-- %s\n", pTmpBuf->usri0_name);

                    pTmpBuf++;
                    dwTotalCount++;
                }
            }
        }
        //
        // Otherwise, print the system error.
        //
        else
            fprintf(stderr, "A system error has occurred: %d\n", nStatus);
        //
        // Free the allocated buffer.
        //
        if (pBuf != NULL)
        {
            NetApiBufferFree(pBuf);
            pBuf = NULL;
        }
    }
    // Continue to call NetUserEnum while 
    //  there are more entries. 
    // 
    while (nStatus == ERROR_MORE_DATA); // end do
    //
    // Check again for allocated memory.
    //
    if (pBuf != NULL)
        NetApiBufferFree(pBuf);
    //
    // Print the final count of users enumerated.
    //
    fprintf(stderr, "\nTotal of %d entries enumerated\n", dwTotalCount);

    return 0;
}