C++如何将USB摄像头设备名称/路径映射到USB端口

Question

是否有任何方法可以根据USB端口顺序获取所有连接的USB摄像头设备？我用这样的东西来获取设备友好的名称和路径，但它没有排序(所以，我不知道哪个连接到哪个端口(：

int _GetUSBCameraDevicesList(std::vector<std::string>& list, std::vector<std::string>& devicePaths)
{
//COM Library Initialization
//comInit();
ICreateDevEnum* pDevEnum = NULL;
IEnumMoniker* pEnum = NULL;
int deviceCounter = 0;
CoInitialize(NULL);
HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL,
CLSCTX_INPROC_SERVER, IID_ICreateDevEnum,
reinterpret_cast<void**>(&pDevEnum));

if (SUCCEEDED(hr))
{
// Create an enumerator for the video capture category.
hr = pDevEnum->CreateClassEnumerator(
CLSID_VideoInputDeviceCategory,
&pEnum, 0);
if (hr == S_OK) {
printf("SETUP: Looking For Capture Devicesn");
IMoniker* pMoniker = NULL;
while (pEnum->Next(1, &pMoniker, NULL) == S_OK) {
IPropertyBag* pPropBag;
hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag,
(void**)(&pPropBag));
if (FAILED(hr)) {
pMoniker->Release();
continue;  // Skip this one, maybe the next one will work.
}

// Find the description or friendly name.
VARIANT varName;
VariantInit(&varName);
hr = pPropBag->Read(L"Description", &varName, 0);
if (FAILED(hr)) hr = pPropBag->Read(L"FriendlyName", &varName, 0);
if (SUCCEEDED(hr))
{
hr = pPropBag->Read(L"FriendlyName", &varName, 0);
int count = 0;
char tmp[255] = { 0 };
while (varName.bstrVal[count] != 0x00 && count < 255)
{
tmp[count] = (char)varName.bstrVal[count];
count++;
}
list.emplace_back(tmp);
//if (!silent) DebugPrintOut("SETUP: %i) %sn", deviceCounter, deviceNames[deviceCounter]);

// then read Device Path
{
VARIANT DP_Path;
VariantInit(&DP_Path);
hr = pPropBag->Read(L"DevicePath", &DP_Path, 0);
if (SUCCEEDED(hr))
{
int __count = 0;
char __tmp[255] = { 0 };
while (DP_Path.bstrVal[__count] != 0x00 && __count < 255)
{
__tmp[__count] = (char)DP_Path.bstrVal[__count];
__count++;
}
devicePaths.emplace_back(__tmp);
}
}
}
pPropBag->Release();
pPropBag = NULL;
pMoniker->Release();
pMoniker = NULL;
deviceCounter++;
}
pDevEnum->Release();
pDevEnum = NULL;
pEnum->Release();
pEnum = NULL;
}
//if (!silent) DebugPrintOut("SETUP: %i Device(s) foundnn", deviceCounter);
}
//comUnInit();
return deviceCounter;
}

日志输出：

1. USB Camera
2. USB Camera
3. FaceCam VGA

你在上面看到的是函数在应该按照这个顺序时给我的顺序：

1. USB Camera
2. FaceCam VGA
3. USB Camera

Answer 1

一切正常，只需对数组使用std::reverse即可。

#include <algorithm>
std::reverse(devicePaths.begin(), devicePaths.end());