However it is implemented, it should be 'named' so that it is obvious to a person reading over the code, that the test is checking for a specific capability.
Agreed. That's part of the point I'm trying to make with Peter.
The is_other test _isn't checking_ for a specific capability! That's the whole point!
apologies... when I said "... the test is checking for a specific capablity." it came across wrong. What I meant was, if we have code like: if (is_file("/some/path/")) { ... } [ where "/some/path/" is a directory in the traditional sense ] The 'checking' is not "does the capability exist" -> rather "is the capability true", where false would be a result of the platform not supporing a valid implementation of is_file() or it isn't an actual file. That said, these is_blah()'s are really tri-state values - not boolean. Should their specification be: int is_file(const char *) where the return values can be: -1 error, and errno is set with the error value 0 false 1 true ? Mathew