Re: [PATCH 0/7] MR3271: windows.devices.usb: Implement IUsbDeviceStatics::GetDeviceSelectorVidPidOnly().

[Rémi Bernon (＠rbernon)]

Rémi Bernon (@rbernon) commented about dlls/windows.devices.usb/usbdevice.c:
> - static const WCHAR *prefix = L"System.Devices.InterfaceClassGuid:="{DEE824EF-729B-4A0E-9C14-B7117D33A817}""
> -
>                             L" AND System.Devices.InterfaceEnabled:=System.StructuredQueryType.Boolean#True"
> -
>                             L" AND System.DeviceInterface.WinUsb.UsbVendorId:=";
> - static const WCHAR *suffix = L" AND System.DeviceInterface.WinUsb.UsbProductId:=";
> - WCHAR *buffer;
> - int length;
> - HRESULT hr;
> -
> - TRACE( "iface %p, vendor %d, product %d, value %p.\n", iface, vendor, product, value );
> -
> - if (!value) return E_INVALIDARG;
> -
> - length = _snwprintf( NULL, 0, L"%ls%d%ls%d", prefix, (INT32)vendor, suffix, (INT32)product );
> - if (length < 0) return E_FAIL;
> -
> - buffer = (WCHAR *)malloc( (length + 1) * sizeof(WCHAR) );

You could probably use a static buffer with a large enough fixed size as the format string is known and as %d has a fixed maximum size, which would save the trouble of the allocation and having to pre-compute the length.