Ruby: All Errno::ERROR constants inherit from SystemCallError

To catch all possible exceptions from a network call, we need to rescue many error classes like this:

Copyrescue SocketError, Errno::ECONNREFUSED, Errno::ECONNRESET, Errno::ECONNABORTED, Errno::EHOSTUNREACH, OpenSSL::SSL::SSLError, MyHttpLib::BadResponse

You can shorten this a bit by rescuing SystemCallError Show archive.org snapshot , which is a base class for all Errno:: exceptions:

Copyrescue SocketError, SystemCallError, OpenSSL::SSL::SSLError, MyHttpLib::BadResponse

Some high-level HTTP client libraries convert these errors into a single base class for easier handling E.g. Http.rb provides a HTTP::Error class and you only need to rescue this one class.