Fri Jan 4 18:32:00 GMT 2008
Jeff Johnston wrote:
> Vincent RiviÃ¨re wrote:
>> Jeff Johnston a wrote :
>>> _isatty is not one of the fundamental syscalls required by newlib.
>>> Remember that newlib's historical origin was to support embedded
>>> platforms and it only required a small set of syscalls to support
>>> the ANSI C plus miscellaneous functions. There is a rough isatty()
>>> implementation in libc/posix that uses fstat, not _isatty.
>>> Platforms that have wanted it have typically just done so directly
>>> in their libgloss implementation or libc/sys (used before libgloss
>>> was created) or they use the libc/posix implementation or they use
>>> the default libgloss/isatty.c version (always returns 1) or they let
>>> libnosys resolve it (always returns 0) just to allow tests to link/run.
>> I understand.
>> But there are 2 problems :
>> 1) isatty() is currently fundamental, because without it, a simple
>> printf() cannot link !
>> isatty() is used at the bottom of libc/stdio/makebuf.c
>> 2) The isatty() implementation in libgloss/libnosys/isatty.c uses the
>> wrong errno. It should only #include <errno.h>, without #undef errno,
>> extern int errno.
> Hmm, there are huge inconsistencies here. The isatty syscall hasn't
> been made compulsory like the other newlib syscalls in that there is
> neither _isatty or _isatty_r calls in the library, but it should have
> been or at the very least, something like the libc/posix isatty
> implementation should have been exposed to be overridden if desired.
> The isatty in libnosys should probably be changed to be consistent
> with other libnosys syscalls and implement _isatty.
> It will take some unravelling to see if adding _isatty_r will break
> things or not for existing platforms. For example, Cygwin is using
> the libc/posix isatty and also uses libc/syscalls which would override
> libc/posix in the case of the same object name.
> I need to look at this a bit.
> -- Jeff J.
Ok, I have checked in patches to both libgloss and newlib. I have
tested x86-linux and mn10300. It should work the same as before for
Cygwin and powerpcle-*-pe because the libc/posix directory supplies
isatty which calls _isatty which is also supplied in libc/posix. The
two stdio routines now call _isatty_r which is always supplied in
libc/reent and calls either _isatty_r or _isatty. Again, Cygwin should
not see a change since it will end up calling the _isatty implementation
For x86-linux, it was also using libc/posix. I added a new isatty
implementation in sys/linux which will override the posix definition.
It works fine according to the test I performed. I might in the future
want to not use the lib/posix directory and have the isatty also name
I changed various libgloss implementations to rename isatty to be
_isatty. Thus, they should hook up with _isatty_r as desired. These
platforms were using the libc/syscalls directory which now has a isatty
implemenation. Libnosys is also renamed its isatty to be _isatty.
If anybody finds a problem, just post it here.
-- Jeff J.
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