Macro declare_plugin_init 

macro_rules! declare_plugin_init {
    ($native_fn:ident) => { ... };
}

Declare a plugin initialization function with automatic wrapper generation

This macro takes a native Rust function and wraps it as an extern "C" function that can be used in declare_plugin!. The native function should have the signature:

fn my_init() -> Result<(), String>

The macro generates a C ABI wrapper function named plugin_init that:

• Calls your native init function
• Handles the FFI error reporting
• Returns appropriate error codes

Example

use mcp_plugin_api::*;
use once_cell::sync::OnceCell;

static DB_POOL: OnceCell<DatabasePool> = OnceCell::new();

// Native Rust init function
fn init() -> Result<(), String> {
    let config = get_config();
     
    // Initialize database
    let pool = connect_to_db(&config.database_url)
        .map_err(|e| format!("Failed to connect: {}", e))?;
     
    // Validate connection
    pool.ping()
        .map_err(|e| format!("DB ping failed: {}", e))?;
     
    DB_POOL.set(pool)
        .map_err(|_| "DB already initialized".to_string())?;
     
    Ok(())
}

// Generate the C ABI wrapper
declare_plugin_init!(init);

// Use in plugin declaration
declare_plugin! {
    list_tools: generated_list_tools,
    execute_tool: generated_execute_tool,
    free_string: utils::standard_free_string,
    configure: plugin_configure,
    init: plugin_init  // ← Generated by declare_plugin_init!
}