How can a customize a file in Library from Library Registry?

FAQ
1

For one of my projects I need to tweak some parameters in a file config.h inside a library, which i loaded from the library registry in PlatformIO. For my other projects i still need the same library as original without the tweaked parameters.

What is the straight forward way in PlatformIO to do this?

Library: LMIC Arduino, Registry ID 852
Need to change something in this file of library

2

Meanwhile i found this solution:

install complete source code of library in lib/mytweakedlib
deleted library.json in root of library

This way i can tweak the code in lib/mytweakedlib/config.h, but i must copy the complete library for this to local lib folder.

Is there a way that only needs the tweaked config.h locally?

3

I did not test it but you can try. You need Redirecting...

So, just explain C++ Preprocessor that you would like to define all macros manually.

[env:...]
build_flags =
  -D _lmic_config_h_
  -D CFG_sx1272_radio=1
   ....
1 Like
4

It works! Thank you very much for helping here.

5

Is it possible to set a #define in this way and prevent it from being redefined? I would like to change a single value in an included library, but it appears that using -D FOO=value is then simply redefined as soon as the preprocessor hits the #define in the library. Unfortunately I can’t use the technique of just defining everything in the header as there is also a class definition in there.

I’d hate to have to fork the whole library just to change a single value that the preprocessor sees, so I’m hoping there’s a way to do this!

Failing that, is there a way to do something like call sed on this file before compilation? Even something hacky like that would work.

6

You can do that with PRE hook on the specific OBJECT file. See Redirecting...