Re: sys/file.h and POSIX

[Marc Recht]

A conforming application cannot make use of facilities outside the
scope of the standard.  This means that if you define
_POSIX_C_SOURCE=200112L you don't want RPC.

I don't said that the application is _strictly_ POSIX conforming. It only wants to use POSIX functions and RPC.
FreeBSD's way seems to be not to define POSIX/XSI (and so) on to _indirectly_ get it and the BSD stuff

4.4BSD (and earlier?) and most derived systems have many conditionals
to prevent namespace pollution in the standards-case.

But more in a kind of aggregation like I want "this and that" (POSIX and stuff..).

So why do we do this?  To prevent screwage of perfectly valid
applications that use the same keywords as system extentions to the
standard.  For instance, the major() macro in <sys/types.h> is a very
common and likely to be used word, so it is not defined in the
standards case to prevent POSIX applications that define a different
major() macro from failing to compile.

Hmm. The questions what makes more problems.. Maybe a solution could be to make a supported way to change the __BSD_VISIBLE from the "outside". Another idea would be to make a WANT_STRICT_POSIX.

Not really.  Conforming applications have no trouble (obviously),
pseudo-conforming applications only need a little work (removing bogus
POSIX keywords that specify conformance), and non-conforming BSD
applications (the majority of software) have no problems.

I had this in mind.
http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap02.html:

A conforming implementation shall meet all of the following criteria:
[...]
4. The system may provide additional utilities, functions, or facilities not required by IEEE Std 1003.1-2001. Non-standard extensions of the utilities, functions, or facilities specified in IEEE Std 1003.1-2001 should be identified as such in the system documentation. Non-standard extensions, when used, may change the behavior of utilities, functions, or facilities defined by IEEE Std 1003.1-2001. The conformance document shall define an environment in which an application can be run with the behavior specified by IEEE Std 1003.1-2001. In no case shall such an environment require modification of a Strictly Conforming POSIX Application (see Strictly Conforming POSIX Application ).

So, defining POSIX should guarantee that a strictly POSIX conforming runs/compiles correctly. But not that a non-strictly POSIX conforming application won't.

FreeBSD's behaviour is consistent with BSD's behaviour.

No. Eg. the rpc example works out-of-the-box on NetBSD 1.6. And only a _very_ small part of the UNIX world is BSD.

Regards,
Marc


"Premature optimization is the root of all evil." -- Donald E. Knuth

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