static libs... is this allowed?

[Somebody]

So I'm working on a project which uses a few static libs:

lib1.lib (support lib)
lib2.lib (support lib)
lib3.lib (support lib)

mylib.lib links to lib1, lib2 and lib3

but I noticed that lib1 has an a.obj file in it, and so does mylib.lib. The
linker seems to toss out the lib1 (or at least the a.obj portion of it)
completely because now the app that uses mylib.lib no longer links in static
version. It says that functions used by mylib.lib -> a.obj (which use
functions from lib1 -> a.obj) don't exist.

any ideas?

 

[Ian Collins]

So I'm working on a project which uses a few static libs:

lib1.lib (support lib)
lib2.lib (support lib)
lib3.lib (support lib)

mylib.lib links to lib1, lib2 and lib3

but I noticed that lib1 has an a.obj file in it, and so does mylib.lib. The
linker seems to toss out the lib1 (or at least the a.obj portion of it)
completely because now the app that uses mylib.lib no longer links in static
version. It says that functions used by mylib.lib -> a.obj (which use
functions from lib1 -> a.obj) don't exist.

any ideas?

Try a group for your platform or tools, this isn't really a C++ question.

 

[Ron AF Greve]

Hi,

So I'm working on a project which uses a few static libs:

lib1.lib (support lib)
lib2.lib (support lib)
lib3.lib (support lib)

mylib.lib links to lib1, lib2 and lib3

but I noticed that lib1 has an a.obj file in it, and so does mylib.lib.
The linker seems to toss out the lib1 (or at least the a.obj portion of
it) completely because now the app that uses mylib.lib no longer links in
static version. It says that functions used by mylib.lib -> a.obj (which
use functions from lib1 -> a.obj) don't exist.

any ideas?

I think you have to be more specific about what tool you use. Do you use VS?
It is very important that every library has the same type of compile (for
instance MT (multithreaded) ).

Libraries do not actually link to eachother (they can depend on eachother
though). When the final app is created everything needed is pulled from the
(static) libraries and put in the final exe. Any dynamic libraries are also
created and go in there own file There is nothing special having multiple
static libraries.

Regards, Ron AF Greve

http://www.InformationSuperHighway.eu

 

[Somebody]

I think you have to be more specific about what tool you use. Do you use

VS? It is very important that every library has the same type of compile
(for instance MT (multithreaded) ).

Libraries do not actually link to eachother (they can depend on eachother
though). When the final app is created everything needed is pulled from
the (static) libraries and put in the final exe. Any dynamic libraries are
also created and go in there own file There is nothing special having
multiple static libraries.

Yeah, I'm using Visual Studio.

My product is a library that provides both DLL and static LIB versions. Both
versions use Detours static lib, LibPNG static lib and ZLib static lib.

LibPNG has a png.c file and thus produces a png.obj file.

My DLL (or LIB) had a png.cpp file and thus produced a png.obj as well.

When I went to build MyApp (that only links to MyDLL (or LIB)), it couldn't
find any of the stuff thats in LibPNGs png.c.

Actually, as I was building MyDLL in static lib format, I would get a
warning from the linker saying "Replacing .\DebugS\png.obj". It linked
everything else from my LibPNG project. It just dumped that one OBJ file.

I got around this by renaming *MY* png.cpp to pngutil.cpp.

 

[Ron AF Greve]

Hi,

Ok, I can imagine there is a problem in that the png static library gets
embedded in your app.exe and in the dynamic library (to be honest I am not
sure about this).

Since you can compile libpng also as DLL you might try that configuration
(you probably need to do the same for zlib then). I wouldn't expect a
conflict with (but its only a guess).


Regards, Ron AF Greve

http://www.InformationSuperHighway.eu

 

[Boris]

[...]Yeah, I'm using Visual Studio.

My product is a library that provides both DLL and static LIB versions.
Both
versions use Detours static lib, LibPNG static lib and ZLib static lib.

LibPNG has a png.c file and thus produces a png.obj file.

My DLL (or LIB) had a png.cpp file and thus produced a png.obj as well.

When I went to build MyApp (that only links to MyDLL (or LIB)), it
couldn't
find any of the stuff thats in LibPNGs png.c.

Actually, as I was building MyDLL in static lib format, I would get a
warning from the linker saying "Replacing .\DebugS\png.obj". It linked
everything else from my LibPNG project. It just dumped that one OBJ file.

I got around this by renaming *MY* png.cpp to pngutil.cpp.

You can set the object file name for any .cpp file in Visual Studio.
Visual Studio does this automatically if you add two .cpp files with the
same name to a project. For the second .cpp file the .obj file created has
the number 1 appended (eg. png1.obj instead of png.obj). That way you
don't need to change the name of any .cpp file.

HTH,
Boris