As finds the first error in chain of {err} that matches target, and if so, sets target to that error value and returns true.

GetCode will try to get 'code' of error if the error is not ierror, it will return 0 otherwise, it will return the 'code'.

Is reports whether any error in chain of {err} matches target.

New returns an error that formats as the given text.

NewWithCode returns an error with supplied message and a specific code.

With will combine new error with the cause and the combined error will have the code of cause error.

Wrap returns an error with additional message.

Wrapf returns an error with additional message.