Indeed, i installed ganache where i deployed a smart contract. I wanted to write a c program that would allow me to call the functions of my smart contract and read the messages. This program would then have to be executed in connected objects. I did some research, but I can't figure out how to do it, but i guess i will use the JSON-RPC protocol, in this case how to call json-rpc from my c program to access my smart contract
Ganache is as server node to ethereum chain and you can using standart ethereum rpc api (attention, look port , default,7545 , but bettet to check, see here more details about configuration ganache https://www.trufflesuite.com/docs/ganache/reference/workspace-default-configuration)
For calling method to only getting data from smart you should using https://eth.wiki/json-rpc/API#eth_call.
For call function and transfer data to smart contact you should to call
Be carefully then formed data to eth_sendTransaction.