C: Windows 没有找到 HARDWARE\DEVICEMAP\SERIALCOMM 即使它可以使用 regedit 找到

Question

我想列出 COM 端口（就像在 'Device Manager' 中看到的那样），但是在运行时。

我厚颜无耻地复制了this site的代码（代码显示在post的末尾），我想我明白了。然而，程序在第 36 行失败，给我错误：

Failed to open key 'HARDWARE\DEVICEMAP\SERIALCOMM' 
Windows reports error: (0x00000002): The system cannot find the file specified.

如果我打开注册表编辑器，我会清楚地看到该文件夹，当我单击它时，我会看到我已连接到我的计算机的设备。

我使用 MinGW 和命令 gcc filename.c

编译了代码

关于如何解决这个问题有什么想法吗？可能是权限问题？ gcc 是否需要一些编译器标志才能让我使用它？

我运行的代码是这样的：

#define WIN32_LEAN_AND_MEAN  // excludes stuff frokm windows.h that we won't need here.
#include <Windows.h>
#include <string.h>
#include <tchar.h>
#include <malloc.h>

void ShowErrorFromLStatus(LSTATUS lResult)
{
    LPTSTR psz;
    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL,
        lResult,
        0,
        (LPTSTR)&psz,
        1024,
        NULL);

    _tprintf(_T("Windows reports error: (0x%08X): %s\n"), lResult, (psz) ? psz : _T("(null)"));
    if (psz)
    {
        LocalFree(psz);
    }
}

int main()
{
    DWORD nValues, nMaxValueNameLen, nMaxValueLen;
    HKEY hKey = NULL;
    LPTSTR szDeviceName = NULL;
    LPTSTR szFriendlyName = NULL;
    DWORD dwType = 0;
    DWORD nValueNameLen = 0;
    DWORD nValueLen = 0;
    DWORD dwIndex = 0;

    LSTATUS lResult = RegOpenKeyEx(HKEY_LOCAL_MACHINE, L"HARDWARE\DEVICEMAP\SERIALCOMM", 0, KEY_READ, &hKey);
    if (ERROR_SUCCESS != lResult)
    {
        printf("Failed to open key \'HARDWARE\DEVICEMAP\SERIALCOMM\' \n");
        ShowErrorFromLStatus(lResult);
        return 1;
    }

    lResult = RegQueryInfoKey(hKey, NULL, NULL, NULL, NULL, NULL, NULL,
        &nValues, &nMaxValueNameLen, &nMaxValueLen, NULL, NULL);

    if (ERROR_SUCCESS != lResult)
    {
        _tprintf(_T("Failed to RegQueryInfoKey()\n"));
        ShowErrorFromLStatus(lResult);
        RegCloseKey(hKey);
        return 2;
    }

    szDeviceName = (LPTSTR)malloc(nMaxValueNameLen + sizeof(TCHAR));
    if (!szDeviceName)
    {
        _tprintf(_T("malloc() fail\n"));
        RegCloseKey(hKey);
        return 3;
    }

    szFriendlyName = (LPTSTR)malloc(nMaxValueLen + sizeof(TCHAR));
    if (!szFriendlyName)
    {
        free(szDeviceName);
        _tprintf(_T("malloc() fail\n"));
        RegCloseKey(hKey);
        return 3;
    }

    _tprintf(_T("Found %d serial device(s) registered with PnP and active or available at the moment.\n"), nValues);

    for (DWORD dwIndex = 0; dwIndex < nValues; ++dwIndex)
    {
        dwType = 0;
        nValueNameLen = nMaxValueNameLen + sizeof(TCHAR);
        nValueLen = nMaxValueLen + sizeof(TCHAR);

        lResult = RegEnumValueW(hKey, dwIndex, 
            szDeviceName, &nValueNameLen,
            NULL, &dwType, 
            (LPBYTE)szFriendlyName, &nValueLen);

        if (ERROR_SUCCESS != lResult || REG_SZ != dwType)
        {
            _tprintf(_T("SerialPortEnumerator::Init() : can't process registry value, index: %d\n"), dwIndex);
            ShowErrorFromLStatus(lResult);
            continue;
        }
        _tprintf(_T("Found port \'%s\': Device name for CreateFile(): \'\.%s\'\n"), szFriendlyName, szDeviceName);
    }

    free(szDeviceName);
    free(szFriendlyName);
    RegCloseKey(hKey);
    return 0;
}

编辑

我现在用 _T("HARDWARE\DEVICEMAP\SERIALCOMM") 调用 RegOpenKeyEx，在第 81 行对 RegEnumValueW 的调用中，我将 szDeviceName 转换为 LPWSTR。 gcc 不再给出任何错误或警告。但是，当运行程序出来的时候，都是

Found 1 serial device(s) registered with PnP and active or available at the moment.
Found port 'C': Device name for CreateFile(): '\.\'

而且我连接的端口（COM3）没有显示。

还有其他建议吗？

Answer 1

感谢Simon Mourier and Ian Abbott！

如编辑中所述，使用 _T("HARDWARE\DEVICEMAP\SERIALCOMM") 调用 RegOpenKeyEx 并将 szDeviceName 转换为 LPWSTR 修复了所有错误。

此外，在第 92 行对 _tprintf() 的调用中使用标识符 %ls 使名称打印正确。

最终的工作代码如下所示：

#define WIN32_LEAN_AND_MEAN  // excludes stuff frokm windows.h that we won't need here.
#include <Windows.h>
#include <string.h>
#include <tchar.h>
#include <malloc.h>
#include <stdio.h>

void ShowErrorFromLStatus(LSTATUS lResult)
{
    LPTSTR psz;
    FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL,
        lResult,
        0,
        (LPTSTR)&psz,
        1024,
        NULL);

    _tprintf(_T("Windows reports error: (0x%08X): %s\n"), lResult, (psz) ? psz : _T("(null)"));
    if (psz)
    {
        LocalFree(psz);
    }
}

int main()
{
    DWORD nValues, nMaxValueNameLen, nMaxValueLen;
    HKEY hKey = NULL;
    LPTSTR szDeviceName = NULL;
    LPTSTR szFriendlyName = NULL;
    DWORD dwType = 0;
    DWORD nValueNameLen = 0;
    DWORD nValueLen = 0;
    DWORD dwIndex = 0;

    LSTATUS lResult = RegOpenKeyEx(HKEY_LOCAL_MACHINE, _T("HARDWARE\DEVICEMAP\SERIALCOMM"), 0, KEY_READ, &hKey);
    if (ERROR_SUCCESS != lResult)
    {
        printf("Failed to open key \'HARDWARE\DEVICEMAP\SERIALCOMM\' \n");
        ShowErrorFromLStatus(lResult);
        return 1;
    }

    lResult = RegQueryInfoKey(hKey, NULL, NULL, NULL, NULL, NULL, NULL,
        &nValues, &nMaxValueNameLen, &nMaxValueLen, NULL, NULL);

    if (ERROR_SUCCESS != lResult)
    {
        _tprintf(_T("Failed to RegQueryInfoKey()\n"));
        ShowErrorFromLStatus(lResult);
        RegCloseKey(hKey);
        return 2;
    }

    szDeviceName = (LPTSTR)malloc(nMaxValueNameLen + sizeof(TCHAR));
    if (!szDeviceName)
    {
        _tprintf(_T("malloc() fail\n"));
        RegCloseKey(hKey);
        return 3;
    }

    szFriendlyName = (LPTSTR)malloc(nMaxValueLen + sizeof(TCHAR));
    if (!szFriendlyName)
    {
        free(szDeviceName);
        _tprintf(_T("malloc() fail\n"));
        RegCloseKey(hKey);
        return 3;
    }

    _tprintf(_T("Found %d serial device(s) registered with PnP and active or available at the moment.\n"), nValues);

    for (DWORD dwIndex = 0; dwIndex < nValues; ++dwIndex)
    {
        dwType = 0;
        nValueNameLen = nMaxValueNameLen + sizeof(TCHAR);
        nValueLen = nMaxValueLen + sizeof(TCHAR);

        lResult = RegEnumValueW(hKey, dwIndex, 
            (LPWSTR)szDeviceName, &nValueNameLen,
            NULL, &dwType, 
            (LPBYTE)szFriendlyName, &nValueLen);

        if (ERROR_SUCCESS != lResult || REG_SZ != dwType)
        {
            _tprintf(_T("SerialPortEnumerator::Init() : can't process registry value, index: %d\n"), dwIndex);
            ShowErrorFromLStatus(lResult);
            continue;
        }
        _tprintf(_T("Found port \'%ls\': Device name for CreateFile(): \'\.%ls\'\n"), szFriendlyName, szDeviceName);
    }

    free(szDeviceName);
    free(szFriendlyName);
    RegCloseKey(hKey);
    return 0;
}

C: Windows 没有找到 HARDWARE\DEVICEMAP\SERIALCOMM 即使它可以使用 regedit 找到

C: Windows not finding HARDWARE\DEVICEMAP\SERIALCOMM even though it can be found using regedit

c

winapi

com-port