Any idea about fixing this 'eclipse cdt -l error' - arduino

Question

I am trying to link my AVR cross target application to my AVR cross target library.
The library is named Lib328P and the application is named LibTest. I have built the library and verified that the .a exists in the filesystem.
I am trying to link the library by Right clicking on the project>Clicking on C/C++ Build> Settings > AVR C++ Linker> Libraries adding Lib328P to the -l category and "${workspace_loc:/Lib328P}"
to the -L category
Here is the output to the console.
**** Build of configuration Debug for project LibTest ****
make all
Building target: LibTest.elf
Invoking: AVR C++ Linker
avr-g++ -Wl,-Map,LibTest.map,--cref -L"C:\Users\kempsa\indigo_workspace\Lib328P" -mmcu=atmega328p -o "LibTest.elf" ./something.o -lLib328P
c:/arduino-0023/hardware/tools/avr/bin/../lib/gcc/avr/4.3.2/../../../../avr/bin/ld.exe: cannot find -lLib328P
make: *** [LibTest.elf] Error 1
**** Build Finished ****
I have looked at the other posts and they suggest removing the lib and .a suffix. I am already doing that. Any help would be appreciated.
Thank you!
Sam

Answer 1

In your case, the linker is expecting to find the file:
C:\Users\kempsa\indigo_workspace\Lib328P\libLib328P.a
Are you sure it is present at that location? Or is it in a subfolder, possibly Release or
Debug?
This is the process that works for me:
When adding a library to be linked with your program, you make two entries. The entries are found on the project properties page by navigating to:
C/C++ Build > Settings
On the right pane, be sure to select whatever Configuration you are building at the top drop down box. (Occasionaly I make changes to the wrong configuration and wonder why those changes do not seem to occur.)
On "Tool Settings" tab is a navigation tree. On that tree, select
AVR C++ Linker > Libraries
On the right pane are two list boxes: Libraries and Libraries Path. These are where you add the two entries.
1.. In the top box, click the plus or + icon. Here you enter just the library base name. This is the library name without the "lib" and without the ".a"
For example, I have one "LibCore328v101".
That will cause the linker to look for a file "libLibCore328v101.a"
2.. In the bottom box, click the plus or + icon. Here you add the path to find that library file.
2a. You can simply type the path to the folder that contains the .a file.
2b. You can click the Workspace... button and navigate to the folder that contains your library. If you keep your libraries and programs in the same workspace this is a better method to specify a path. I use this, in in my example this text is created
"${workspace_loc:/LibCore328v101/Release}"
This is essentially a relative path to the library. This means you can create an entire duplicate of your workspace and all the library includes will still be correct.
When you see the linker output in the console window, you should see both options. In my example these are:
-lLibCore328v101 (lower case ell)
-L"F:\arduino-src\tt-wb-trunk-hg\LibCore328\Release" (upper case ell)
You can see that the Eclipse plugin has converted the relative path to the current absolute path. The linker will internally add the "lib" and ".a" to the library name.
You can repeat this process adding as many libraries and paths as needed.
For your multi-target programs, you create a different configuration for every build target. So instead of Debug and Release, you have "DebugNano" "DebugTiny", etc. For each configuration, change the path to the library.