Overridable setup, loop and main

[cipriancraciun]

Following the same pattern as in the case of serialEvent, I'm proposing the following:

• provide an empty implementation of the setup and loop functions;
• mark all three functions (setup, loop and main) as __attribute__ (weak) so that the user is able to override them with customized versions;

P.S.: Granted that if the user overrides main he must manually call init.

P.P.S.: I'll provide in a minute the needed patch.

[ffissore]

Thank for your patch. However, after having discussed it, we preferred to simplify the life of the developer making the IDE start with the BareMinimum sketch, thus solving the need to code them, even if empty.
Does this address your issue?

[cipriancraciun]

Unfortunately my use case is a little bit different and the proposal of an "empty" template sketch doesn't actually help me.

I use the Arduino in an automation project, and I use it without the IDE. (I.e. I use a customized build system which relies only on GCC, avr-libc, and various generic build tools -- this is open-sourced at https://github.com/cipriancraciun/arduino-workbench )

Also in my case I use the Arduino C/C++ "standarrd library" only for the initialization, serial and pin operations, because I've written my own main function which replicates part of Arduino's main. But linking with Arduino's library I get duplicate symbols for main and missing symbols for setup and loop. (I also have open-sourced some of those libraries at https://github.com/cipriancraciun/arduino-libraries )

All in all if you don't apply this it doesn't bother me much as I use a custom installation.