Another conformance question... This time fputs().

[David Schultz]

On Wed, Mar 03, 2004, Bruce Evans wrote:
> This is the only failure case.  It bogusly returns EOF instead of boolean
> true.  We can set errno to EBADF here if we have no idea why __SRW is
> clear.  But we should know.  I think the cases are:
> (1) a normal fopen() for reading only.  Then EBADF is correct.
> (2) funopen() with no writer, or fropen().  I think this can be determined
>     by checking the function pointer that we write through.  Then write is
>     just unsupported and an errno like ENOTSUP is better than EBADF.
> (3) otherwise, we will call the underlying function and there is no problem
>     here.  The underlying function just needs to set errno if it fails, and
>     old ones probably don't.
> So the only immediate problem with returning EBADF in all cases seems to be
> in case (2) which is not very interesting.

One could argue that EBADF is a perfectly reasonable error code to
return in case (2) as well.  It is consistent with the way other
types of stdio streams work.  Specifically, if the stream isn't
writable (either because it was opened read-only and we don't have
permission or because it was opened without a writefn and we don't
support it) then we should get a single error code that reflects
the fact that the stream isn't writable.  The fputs(3) man page
even says:

	[EBADF]		The _stream_ argument is not a writable stream.

It doesn't say anything about why the stream is not writable.
Thus, there shouldn't be a problem with simply setting errno to
EBADF in all failure cases in __swsetup().