solana/sdk/src/native_program.rs

use account::KeyedAccount;
use pubkey::Pubkey;

// All native programs export a symbol named process()
pub const ENTRYPOINT: &str = "process";

// Native program ENTRYPOINT prototype
pub type Entrypoint = unsafe extern "C" fn(
    program_id: &Pubkey,
    keyed_accounts: &mut [KeyedAccount],
    data: &[u8],
    tick_height: u64,
) -> bool;

// Convenience macro to define the native program entrypoint.  Supply a fn to this macro that
// conforms to the `Entrypoint` type signature.
#[macro_export]
macro_rules! solana_entrypoint(
    ($entrypoint:ident) => (
        #[no_mangle]
        pub extern "C" fn process(
            program_id: &Pubkey,
            keyed_accounts: &mut [KeyedAccount],
            data: &[u8],
            tick_height: u64
        ) -> bool {
            return $entrypoint(program_id, keyed_accounts, data, tick_height);
        }
    )
);

/// Reasons a program might have rejected an instruction.
#[derive(Debug, PartialEq, Eq, Clone)]
pub enum ProgramError {
    /// Contract's transactions resulted in an account with a negative balance
    /// The difference from InsufficientFundsForFee is that the transaction was executed by the
    /// contract
    ResultWithNegativeTokens,

    /// The program returned an error
    GenericError,

    /// Program's instruction token balance does not equal the balance after the instruction
    UnbalancedInstruction,

    /// Program modified an account's program id
    ModifiedProgramId,

    /// Program spent the tokens of an account that doesn't belong to it
    ExternalAccountTokenSpend,
}