I made a static library with GCC. Building of the library was OK.
When I use it the linker throws undefined reference errors on some functions. But nm says the functions are defined and exported in the static library (marked with T). I know about the linking order that I need to put the libraries after that module that needs them so this can not be a problem.
The static library was built from 3 C files. A.c B.c and D.c The D module depend on A and B (includes their headers).
No problem when I use functions from A and B but when I try to use any function from D I get undefined reference errors on them.
If I move these functions in A or B it works. But not if they are in the D module.
I’m completely run out of ideas what’s going on or what is I’m overlooked.
I’m using Code::Blocks and working with plain C files.
I found out that I added A .cpp file to my project and I just renamed it to .c. I chose C language instead of C++ when I created the project. I did’t think this could cause problems
I thought the file extension decides when the IDE chooses between gcc and g++. But not. In Code::Blocks if you add a file with a .cpp extension it will use g++. If you add a file with a .c extension it will use gcc. But if you rename the file it will use the same compiler. You have to change it explicitly in the project options.
That D module was built using g++ instead of gcc.
I realized this when I set the IDE to show me the entire command line when building not just “Compiling foo.c”.