Re: [Mingw-users] what is missing when --export-all-symbols is removed

[Kuba O. <ku...@ma...>]

On Saturday 14 February 2004 03:40 pm, Danny Smith wrote:
>  --- Heiko Gerdau <> wrote:
> > On Saturday 14 February 2004 00:41, Kuba Ober wrote:
> >
> > The relevant difference to the GNU Linux link process is the windows
> > specific export/import process of symbols. Unfortunately to build Qt you
> > have to use the linker switch --export-all-symbols. Without it the link
> > time drops dramatically but the linker will also complain about
> > unsresolved symbols. I actually do not understand why. In the source code
> > every symbol is properly handled with dllexport/dllimport and it should
> > work.
>
> Need some help. I see similar problems with other C++ dlls and am (slowly)
> working g to work up patch and testcases.
> What kind of symbols do not get marked as dllexport in QT?  Typeinfo?
> Vtables?. Do headers use pragma interface/pragma implementation?

Attached is what examples/hello (from Qt/Win enterprise) are missing from Qt 
when libqt-mt.a (the export library) was obtained when linking w/o 
--export-all-symbols.

I first linked it to (deficient) libqt-mt.a export library, then w/o 
mentioning that library at all so that you can see that in fact there's a lot 
more stuff missing when the import library is not linked with.

Thus, the import library contains *some* needed symbols but not all of them. 
Hopefully the files will aid in your debugging.

log.gz - with qt-mt and qtmain
log.d.gz - same, mangled symbols
log-noqt.gz - without linking to qt at all -- no qt-mt nor qtmain given to 
linker (so that you can see what *is* exported by Qt)
log-noqt.m.gz - same, mangled symbols

In order to compare the logs (say log and log-noqt), ungzip, sort and feed to 
diff -u. Works nicely.

Cheers, Kuba