[lgessler]

Don't you think using errno is a cleaner pattern? Conflating the place where you expect a value and the place where you check for a reason why no value could be produced can be dangerous. (E.g.: if the value is an integer, an error code is mistaken for a value.)

[matheusmoreira]

Linux returns negated errno constants. This produces error codes which are outside the range of valid values. I think it's more sane than errno.

Functions of my own design almost always return status codes only. Actual data is returned through pointer parameters. This allows me to quickly determine the exact set of variables that are affected by any function call.