Multiple sketch failing to compile at 1.6.10

Community Suggestions for the Arduino Project
1

Hello everyone,

Something big has changed between 1.6.9 and 1.6.10 because at .10 the project does not compile with "'xyz' was not declared in this scope" all over the place.

Thanks

3

It is the way the IDE stitches together multiple sketch projects, the order in which it puts them together and compiles them I think.

I have gone back to version 1.6.9 which works.

5

Arduino IDE release notes are here https://www.arduino.cc/en/Main/ReleaseNotes

Every release brings some changes, whether they are significant or not depends on the sketch. New build methods, and new compiler changes can and do affect how code is compiled. I have encountered this several times, either code does not compile or runs differently on newer releases of the IDE. Personally my approach is to hunt down the problems and fix them. Often this improves the code and makes it proof to future changes, e.g. correct use of "volatile". Staying on a specific point release is not a sustainable option.

In particular 1.6.10 included :

[ide]
* A lot of bugfixes to builder:
  https://github.com/arduino/arduino-builder/issues?q=milestone%3A1.3.19+is%3Aclosed

[core]
* avr: toolchain updated to latest Atmel release 3.5.3 http://distribute.atmel.no/tools/opensource/Atmel-AVR-GNU-Toolchain/3.5.3/
  The updated tools are now binutils-2.26, gcc-4.9.2, avr-libc-2.0.0, gdb-7.8

Both of which might have noticeable differences on compilation.

If you have a problem, post the error log and if possible a small example that shows the problem.