There is Alexander Trufanov's free book (in Russian) on programming for Symbian 9.x with many code samples.[0]
Also, as example of complex apps, there is code of Lonely Cat Games' X-plore[1] & ProfiMail[2] apps, released to Public Domain by LCG devs in 2015-2016.
Another one Symbian open-source app that I like: `fshell` — Symbian equivalent of bash + telnet + a posix-like set of command-line tools.[3]
And the latest app in development: S60Maps — OpenStreetMap & GPS tracker.[4]
FTR, Actually there is an experimental Symbian OS emulator for Linux & Windows.[5]
P.S.: And off course there are tons of useful stuff collected by "Symbian Archive" wiki.[6,7]
Also, as example of complex apps, there is code of Lonely Cat Games' X-plore[1] & ProfiMail[2] apps, released to Public Domain by LCG devs in 2015-2016.
Another one Symbian open-source app that I like: `fshell` — Symbian equivalent of bash + telnet + a posix-like set of command-line tools.[3]
And the latest app in development: S60Maps — OpenStreetMap & GPS tracker.[4]
FTR, Actually there is an experimental Symbian OS emulator for Linux & Windows.[5]
P.S.: And off course there are tons of useful stuff collected by "Symbian Archive" wiki.[6,7]
[0] https://github.com/trufanov-nok/SymbianBook_ru
[1] https://github.com/Symbian9/X-plore_free
[2] https://github.com/Symbian9/ProfiMail_free
[3] https://sourceforge.net/p/fshell/code/
[4] https://github.com/artem78/s60-maps
[5] https://github.com/EKA2L1/EKA2L1
[6] https://mrrosset.github.io/Symbian-Archive/
[7] https://github.com/mrRosset/Symbian-Archive