Mail Archives: cygwin/2005/10/05/17:30:24
----- Original Message -----
From: "John W. Eaton"
Sent: Thursday, 6 October 2005 09:13
> On 6-Oct-2005, Danny Smith wrote:
>
> | Building libstdc++.dll may be a "hard problem" for a mathematician or
> | for libtool, but this is how an ordinary person coud do it.
> |
> | dlltool --output-def libstdc++.def --export-all libstdc++.a
> | gcc -shared -olibstdc++.dll -Wl,--out-implib,libstdc++.dll.a \
> | libstdc++.def libstdc++.a
> |
> |
> | The main problem after that is in getting rid of the need for auto-import of
> | data objects by marking header files appropiately.
>
> The other main problem after that is that the C++ ABI has been
> changing, so having only one version of the library would cause
> trouble. But maybe that is not as big a problem now as it was in the
> past? OTOH, surely there will be some changes to the library in the
> future, so it seems that it would be a good idea to be able to have
> multiple versions of libstdc++.dll.a installed simultaneously? Or is
> this not possible for some reason?
Possible, yes (STLport does this without libtool) , and unfortunately necessary.
I do this, when in a playful mood:
gcc -shared -olibstdc++-${LIBSTDCP_VERSION}.dll \
-Wl,--out-implib,libstdc++-${LIBSTDCP_VERSION}.dll.a \
libstdc++.def libstdc++.a
and then link "libstdc++-${LIBSTDCP_VERSION}.dll.a" to libstdc++.dll.a in my
gcc-version-specific dir:
(lib/gcc/mingw32/__GNUC__.__GNUC_MINOR__.__GNUC__PATCHLEVEL )
There was an old article that I once pulled off the net entitled:
"DLL Maintenance Made Easy
Writing a DLL can seem deceptively easy-until it's time to revise it."
by Geoff Vandegrift
that advised on how to maintain class backward compatibility and so avoid the
versioning woes.
But, with libsupc++/libstdc++ that won't be possible for awhile, especially if
some people want Dwarf2 EH unwinding and others want SjLj.
Danny
>
> jwe
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