How to programmatically check Internet bandwidth in VC++?

Question

I need to find the bandwidth available at a particular time. The code must be developed in Visual C++ or in .Net family . If anyone knows how, please help me out.

Answer 1

If you mean the current network utilisation, you can call

DeviceIoControl(hDevice, OID_GEN_STATISTICS, ...)

on Vista and above to get the device-specific information. Otherwise, call GetIpStatisticsEx for system-wide information or use WMI's Win32_PerfRawData_Tcpip_NetworkInterface.

Trying to get the "available" bandwidth by attempting to saturate the connection is not a sensible or reliable measure. Just try some of the online speed tests available, and consider that it involves non-scalable bandwidth, and is susceptible to congestion control, QoS and traffic shaping.