When building a project with ESP32 / EP8266 MCU, I noticed that the build time (in fact the compilation time) takes much longer than when I use an Arduino or eg. a Teensy.
* Typical compile time ESP32 : 20 seconds
* Typical compile time Teensy : 2 seconds (note : first build may take 20s as well, subsequent builds are much faster)

I think the difference is because in the ESP case, all Espressif libs are being recompiled, even if they are not changed. With the Teensy it looks like only the source files which have been modified are being compiled.

Is there a solution to this ? Are there Visual Micro or Visual Studio settings which can improve this ?
For fast cycle unit testing, there is a big advantage for a 2s build vs 20s builds.

Thanks!

Ok, so I took two basic example projects, included with each processor.
I then built them,
then change some unimportant parameter and build them again.

All four outputs are attached.

Timings measured are :
Teensy first build : 16.6s
Teensy next build : 3.6s
ESP32 first build : 30s
ESP32 next build : 12.7s

When looking at the verbose output, I see that also for the ESP32 it is using previously compiled file.
So I guess it is just due to the amount of libraries involved that the build takes a bit longer, which means there is probably nothing really wrong.

The ESP32 executable is also significantly larger (> 600K), even with only a simple example. (I have the feeling that FreeRTOS is being included, whether you use it or not).

Anyway, thanks for your support.