Cygwin linking model (Was: [jamboost] Nightly zip: tests regression and library_order fail under Cygwin)

From: Vladimir Prus (ghost_at_[hidden])
Date: 2005-01-25 04:22:55

Hi Niklaus,

> Thank you very much for fixing the other test cases under cygwin.
> The errors with regression an library_order still remain.
> Running "r.exe" pops up a windows complaining about a missing helper.dll
> which I happened to find in my cygwin-root

Okay, now I finally have working cygwin installation. Looks like cygwin can't 
be installed on Samba mounted drive -- which is that I've was trying to do 
previously. The system is not always accessible to me, but still it's 
something.

> > Verzeichnis von C:\Programme\cygwin\tmp\tmpffp1m3\libs\bin\gcc\debug
> >
> >25.01.2005 08:39 15'499 helper.dll
> > 1 Datei(en) 15'499 Bytes
>
> Copying this file to bin/r.test/gcc/debug (where r.exec resides) allowed
> me to run r.exe.

Looks like LD_LIBRARY_PATH variable has no effect on cygwin. I've committed a 
fix, which makes this test pass on cygwin.

> library_order :
> "['/cygdrive/c/downloads/boost-build/test/../jam_s
> c/bin.cygwinx86/bjam',
> '-sBOOST_BUILD_PATH=/cygdrive/c/downloads/boost-build/te
> t', '-d0', '--quiet', 'gcc']" returned 1
> STDOUT ============
> ...skipped <pbin/gcc/debug>main.exe for lack of <pbin/gcc/debug>liba.dll...
> ...failed updating 2 targets...
>
> STDERR ============
> bin/gcc/debug/a.o(.text+0x7): In function `_Z1av':
> /tmp/tmpgS5i8T/a.cpp:6: undefined reference to `b()'

I need help with this issue. The problem is that there's a file a.cpp:

void b();

void a()
{
b();
}

which is compiled into DLL. The 'b' function is defined in another DLL, that 
'a' is not linked too (intentionally). Seems like this causes the error. Now 
the question -- anybody knows why. Does cygwin require that another DLL be 
given during linking a.dll? Does it require __dllimport on b?

If that's the case, then the test just makes no sense for cygwin and I'll 
remove it.

And BTW, I get a some other failures on cygwin -- for example, the 'stage' 
test. I wonder why it works for you :-/

- Volodya