external_lib build error using visual code

[kalbani]

I start using 2.2.0 SDK and had this error when building zephyr samples external_lib using nrf52833dk_nrf52833.

the problem as show in image:

after some research I found in this question that seems same with my problem: https://devzone.nordicsemi.com/f/nordic-q-a/70189/external_lib-not-compiling-out-of-the-box/288792 , which suggest to do the build using bash and it's work fine:

the question is how do I solve the error in visual code and build it there? 

[Vidar Berg]

Hello,

The GNU Makefile used to build the external library has not been made compatible with Windows. The reason it fails to build here, is that on Windows, the 'mkdir' command will not recognize the '-p' option being used by the Makefile at this line: 

https://github.com/nrfconnect/sdk-zephyr/blob/2a906fc06280a6f64fa6c144e654e2347655c953/samples/application_development/external_lib/mylib/Makefile#L12 

In other words, to make this work on Windows, the Makefile will have to be modified. Here is a stack overflow post I found which discusses the same problem: https://stackoverflow.com/questions/3228306/portable-makefile-creation-of-directories.

But what is your goal with using this sample? Is it to build an external library with a different build system, or to see how you can include a pre-compiled library in your project?

Best regards,

Vidar

[kalbani]

Hello Vidar

thank you for your answer. My goal is to include LCD library into my project, the library contain .h and .c files. So O sow this is the best way to include the library to my project. 

kalbani

[Vidar Berg]

Hello kalbani,

It sounds like it would be easier and better to just add the library sources to your project by editing the CMakelists.txt file in your project folder. 

target_sources(app PRIVATE src/main.c)
target_sources(app PRIVATE src/lcd_lib/<library source>.c)
.
.
.
# Add include paths if neccessary 
zephyr_library_include_directories(
  src/lcd_lib
  )

[kalbani]

I tried this method but I faced this error (undefined reference to ' variable ' ) when compiling.

[Vidar Berg]

Where is this variable declared and where is it being referenced from? Also, have you verified that the source file which defines this variable is included in your build? 

[kalbani]

All variable are declare in  lcd_lib.h in src/lcd_lib file. I add the script that you send it to CMakelists.txt file. 

what do you mean by verified source file ?

[Vidar Berg]

It is hard to say what is wrong without more information. Any chance you can upload your project/library here or in a private ticket?

[kalbani]

I found what cause this error is when declaring the variables need static term.