Getting the Windows System Error Code title/description from it's hex number

Question

I'm messing around with some windows functions using p/invoke. Occasionally, I get an error code that is not ERROR_SUCCESS (such an odd name).

Is there a way to look these up within the program? Forexample, if I get error 1017. Can I tell the user

The system has attempted to load or restore a file into the registry, but the specified file is not in a registry file format. (ERROR_NOT_REGISTRY_FILE: 0x3F9)

Instead of

Error Code: 1017

Answer 1

I'm not sure if there's a niifty .NET wrapper, but you could call the FormatMessage API using P/Invoke.

See this answer for how it would normally be called from native code. Though the question refers to grabbing error codes from HRESULTs, the answer also applies for retreiving codes from the regular OS error codes coming from GetLastError/GetLastWin32Error).

EDIT: Thanks Malfist for pointing me to pinvoke.net, which includes alternative, managed API:

string errorMessage = new Win32Exception(Marshal.GetLastWin32Error()).Message;
Console.WriteLine(errorMessage);

Answer 2

Yes there's a function that does that but I don't remember what it is. In the mean time, you can use the error lookup tool (Tools->Error Lookup) to see what a particular code means from within Visual Studio.