I have a strange problem with gdc. The linker reports undefined references to symbols, but exactly those symbols exist in the library that I'm linking into the executable. The error message I get is:

C:\Users\Benjamin\AppData\Local\Temp\cc4pUOfp.o:main.d:(.text+0x3a): undefined reference to `_D6thBase2io8writeflnFAyaYm'

But:

nm libthBase64d_mingw.a | grep writefln
000000000003c9b2 T _D6thBase2io8writeflnFAyaYm

I'm building with:

gdc -m64 -I"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\druntime\import" -I"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos" -I"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\thBase\src" -fversion=NOGCSAFE -o "test.exe" -L"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos" -L. -lthBase64d_mingw -debuglib=phobosnogc64d_mingw -Wl,--verbose=2 -defaultlib=phobosnogc64d_mingw -v -pipe -nostdinc main.d

The verbose output of the linker also shows that it finds the correct library file:

attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/libthBase64d_mingw.dll.a failed
attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/thBase64d_mingw.dll.a failed
attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/libthBase64d_mingw.a failed
attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/thBase64d_mingw.lib failed
attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/libthBase64d_mingw.dll failed
attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/thBase64d_mingw.dll failed
attempt to open C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos\libthBase64d_mingw.a failed
attempt to open ./libthBase64d_mingw.dll.a failed
attempt to open ./thBase64d_mingw.dll.a failed
attempt to open ./libthBase64d_mingw.a succeeded

Any ideas what is going wrong here?

Kind Regards
Benjamin Thaut

Am Mon, 18 Mar 2013 08:07:43 +0100
schrieb Benjamin Thaut <code@benjamin-thaut.de>:

> I have a strange problem with gdc. The linker reports undefined references to symbols, but exactly those symbols exist in the library that I'm linking into the executable. The error message I get is:
> 
> C:\Users\Benjamin\AppData\Local\Temp\cc4pUOfp.o:main.d:(.text+0x3a): undefined reference to `_D6thBase2io8writeflnFAyaYm'
> 
> But:
> 
> nm libthBase64d_mingw.a | grep writefln
> 000000000003c9b2 T _D6thBase2io8writeflnFAyaYm
> 
> I'm building with:
> 
> gdc -m64 -I"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\druntime\import" -I"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos" -I"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\thBase\src" -fversion=NOGCSAFE -o "test.exe" -L"C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos" -L. -lthBase64d_mingw -debuglib=phobosnogc64d_mingw -Wl,--verbose=2 -defaultlib=phobosnogc64d_mingw -v -pipe -nostdinc main.d
> 
> The verbose output of the linker also shows that it finds the correct library file:
> 
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/libthBase64d_mingw.dll.a
> failed
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/thBase64d_mingw.dll.a
> failed
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/libthBase64d_mingw.a
> failed
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/thBase64d_mingw.lib
> failed
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/libthBase64d_mingw.dll
> failed
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos/thBase64d_mingw.dll
> failed
> attempt to open
> C:\Users\Benjamin\Documents\d-projects\Spacecraft-git\game\..\..\phobos\libthBase64d_mingw.a
> failed
> attempt to open ./libthBase64d_mingw.dll.a failed
> attempt to open ./thBase64d_mingw.dll.a failed
> attempt to open ./libthBase64d_mingw.a succeeded
> 
> Any ideas what is going wrong here?
> 
> Kind Regards
> Benjamin Thaut

Could it be this: http://stackoverflow.com/questions/8640642/gcc-link-order-changed

Something changed in ld some time ago and the order in which libraries are passed to ld is now important. The library which defines _D6thBase2io8writeflnFAyaYm must be passed to ld first, the lib/object file using it second.

Am 18.03.2013 09:51, schrieb Johannes Pfau:
>
> Could it be this:
> http://stackoverflow.com/questions/8640642/gcc-link-order-changed
>
> Something changed in ld some time ago and the order in which libraries
> are passed to ld is now important. The library which defines
> _D6thBase2io8writeflnFAyaYm must be passed to ld first, the lib/object
> file using it second.
>

So this is a bug in gdc? Shouldn't gdc always pass the object files to the linker first? I noticed that if I change the build command to

gdc -m64 -g -fno-inline-functions -fdebug -I"C:\Users\Benjamin\Documents\d-projects\thBase\src\..\..\druntime\import" -I"C:\Users\Benjamin\Documents\d-projects\thBase\src\..\..\phobos" -fversion=NOGCSAFE -fversion=MEMORY_TRACKING -fdeps="Debug Lib GDC\thBase.dep" -nostdinc -O0 -c -o "Debug Lib GDC\thBase.obj" @"Debug Lib GDC\thBase.build.rsp"

It works correctly.

Thanks for the tip.

Kind Regards
Benjamin Thaut