Anatomy of an Anchor Program

Anchor Overview

Anchor is a framework that reduces Solana program boilerplate. It provides:

• **Macros** for account validation (`#[account]`, `#[derive(Accounts)]`)

• **Auto-generated IDL** — interface definition for clients

• **Built-in serialization** via Borsh

• **Error handling** with custom error codes

Program Structure

use anchor_lang::prelude::*;

declare_id!("YourProgramIdHere");

#[program]
pub mod my_program {
    use super::*;

    pub fn initialize(ctx: Context<Initialize>) -> Result<()> {
        let config = &mut ctx.accounts.config;
        config.authority = ctx.accounts.authority.key();
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(init, payer = authority, space = 8 + Config::INIT_SPACE)]
    pub config: Account<'info, Config>,
    #[account(mut)]
    pub authority: Signer<'info>,
    pub system_program: Program<'info, System>,
}

#[account]
#[derive(InitSpace)]
pub struct Config {
    pub authority: Pubkey,
}

Key Components

• `declare_id!` — sets the program's public key

• `#[program]` — marks the instruction handler module

• `Context<T>` — provides validated accounts to each handler

• `#[account]` — marks a struct as a Solana account (auto-adds 8-byte discriminator)