Building Composable Programs

Cross-Program Invocations (CPIs)

Chapter 5: Building Composable Programs

Design programs for composability using CPIs.

• Key Points:

  • Expose instructions for CPIs.

  • Use PDAs for shared state.

  • Example: Calling another program.

• Code Example:

pub fn call_other_program(ctx: Context<CallOther>, data: u64) -> Result<()> {
    let cpi_program = ctx.accounts.other_program.to_account_info();
    let cpi_accounts = other_program::accounts::DoSomething {
        // Accounts here
    };
    let cpi_ctx = CpiContext::new(cpi_program, cpi_accounts);
    other_program::do_something(cpi_ctx, data)?;
    Ok(())
}

• Interactivity: Simulate calling another program and observe the interaction.