13 Jun
2017
13 Jun
'17
6:01 p.m.
Emil Dotchevski wrote:
If error codes are treated as "the error", then the error domain is limited to a single function. Consider these two functions:
int f1(....); //returns 0 on success, 1-f1_error1, 2-f1_error2 int f2(....); //returns 0 on success, 1-f2_error1, 2-f2_error2
If f2 calls f1, if the error is communicated by an error code, f2 _must_ translate the error condition from the domain of f1 errors, to the domain of f2 errors. And this must be done at every level, which introduces many points in the code where subtle errors may occur, and that is in error handling code which is very difficult to test and debug.
That's exactly the problem std::error_code solves, as it's a (code, domain) pair, so there's no need to translate.