Re: HELP: GCC 2.95.3 Thread Safe IO

[Phil Edwards <pedwards at disaster dot jaj dot com>]

On Tue, Nov 06, 2001 at 11:03:34AM -0500, Paul Dubuc wrote:
> At this point the best option I can think of is to upgrade the libstdc++
> to V3.

Glad you noticed; the libstdc++ mailing list is only for the V3 code.
The library shipped with GCC 3.x has been almost completely rewritten,
and the libstdc++-v2 library is unmaintained.

(That's as polite a way as I can think of saying, "libstdc++-v2 is
nonconforming to the standard, is probably buggy as freak, and we don't
much care."  :-)


> I have downoaded that source and libio/genops.c does have more
> _IO_MTSAFE_IO locks in place.  Is thread safe IO fully implemented in
> this library?  What confguration or make option is needed to define
> _IO_MTSAFE_IO?

In 3.0 by default the libio/* stuff is entirely unused.  Threading largely
depends on your C library in 3.0.x.  Check out

    http://gcc.gnu.org/onlinedocs/libstdc++/27_io/howto.html

and FAQ 5.6 in

    http://gcc.gnu.org/onlinedocs/libstdc++/faq/index.html

If you can upgrade, you should be fine.  Which brings you to...


> Can I use libstdc++-v3 with GCC 2.95.3 (without upgrading the compiler
> to 3.0.2)?  If I can, are there special build instructions.

"An older version" and "heck yes," respectively.

    http://gcc.gnu.org/libstdc++/status.html

The online documentation that you've read is for the most recent version;
for the older snapshots you'll need to read the stuff in the docs directory
instead, after you download and unpack.

Using libstdc++-v3 with GCC 2 is not recommended at all; it's possible with
the older library snapshots, but the older snapshots are lacking lots of
bug fixes.


Phil

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