Lectura rápida
Empieza por la explicación más corta y útil antes de profundizar.
The Rust crate (solana-program) providing the core types and syscalls for on-chain program development. It includes: entrypoint!, msg!, AccountInfo, Pubkey, ProgramResult, invoke/invoke_signed, and system instruction builders. This crate compiles to SBF and must be used instead of solana-sdk for on-chain code.