Question

Are there any standards for error code handling? What I mean by this is not how a particular error event is handled but what is actually returned in the process. An example of this would be when an error in opening a file is identified. While the open() function may return its own value, the function that called the open() function may return a different value.

Answer 1

I don’t think ther’s a standard, all errors must be detected and handled (the caller should always handle errors).
in Unix in general:

• the standard C library for exemple always return -1 on fail and set the global variable errno to the correct value.

• Some libraries for example return NULL for inexistant field rather than aborting.

• You should always return as much useful information as possible.

Hope this help.

Regards.