The latest GCC version is 14.2.1. I want to try out new GCC 15 features. I followed these instructions to build the toolchain from source: https://askubuntu.com/questions/1513160/how-to-install-gcc-14-on-ubuntu-22-04-and-24-04. They translate very well to the latest experimental source available as an archive, 6 days old GCC 15-20250223.
I installed Linux Lite (an Ubuntu derivative) on an older laptop. Building took a little more than a day. The only package that I had to install before building was flex, the fast lexical analyzer generator. Building that was easy. After the full toolchain build completed, I had this happy report:
I tested it from the command line with an existing OO project: C++ callbacks and templates .
All worked 
. Now I can try out some experimental features, such as "dual return". GCC 15 can return both a status and a value. This can make code that has to check if a call was successful, and that wants to retrieve a value (calculation, object,string), simpler
