Attribute Macro ic_cdk::post_upgrade

#[post_upgrade]

Register the canister_post_upgrade entry point of a canister.

This attribute macro will export the function canister_post_upgrade in the canister module.

The function under this attribute must have no return value.

Each canister can only have one canister_post_upgrade entry point.

Example

#[post_upgrade]
fn post_upgrade_function() {
    // ...
}

You can specify a guard function to be executed before the post_upgrade function. When the guard function returns an error, the post_upgrade function will not proceed.

fn guard_function() -> Result<(), String> {
    // ...
}
#[post_upgrade(guard = "guard_function")]
fn post_upgrade_function() {
    // ...
}