library using library?

[David Soukal]

Hello,

I have an interesting problem that I'm tackling with. I'm sure there
must be some obvious solution...

I have this big project. It's composed of several *.lib modules. Now,
one of the modules uses IJG JPEG library. But, another module needs to
use *modified* verzion of the library: the application displays images -
for that it uses "normal" jpeg-6b library. However, some functionality
is required that modifies the jpeg files as we need - this is the job of
the other, modified, library.

Now, when I link the application it crashes. After a few hours, we've
found out that it's because the code that should be calling functions
from B.jpeg6b in fact calls A.jpeg6b. The linker didn't even complain.

Now, since the IJG Jpeg-6b is in C not in C++, we cannot use
"namespace" s to seperate these two.

Has anybody met this problem before?

Formally, it could be stated as,

an application must be linked with libraries A, B, both define a
function f(), how do I make sure that the proper function, i.e. A::f or
B::f gets called?

THANKS!

David

[Brian Gough]

David Soukal <ds******@bingh amton.edu> writes:

Now, when I link the application it crashes. After a few hours, we've
found out that it's because the code that should be calling functions
from B.jpeg6b in fact calls A.jpeg6b. The linker didn't even complain.

Now, since the IJG Jpeg-6b is in C not in C++, we cannot use
"namespace" s to seperate these two.

Has anybody met this problem before?

The jpeg library header files contain a set of macro definitions for
all the external function names, so you can change them in one place
(e.g. to add a version number suffix) and recompile the library.

--
Brian Gough

Network Theory Ltd,
Publishing Free Software Manuals --- http://www.network-theory.co.uk/