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Function Visibility

Solidity

Functions can have the following visibility modifiers:

  • public: Accessible externally and internally.
  • private: Restricted to usage within the contract where it's defined.
  • internal: Limited to use within the contract where it's defined or the contract that inherits it.
  • external: Accessible only externally.

contract FunctionsVisibility {
function publicFunction() public {/* ... */}
function _privateFunction() private { /* ... */ }
function _internalFunction() internal { /* ... */ }
function _externalFunction() external { /* ... */ }
}

Move

Doesn't have equivalents to Solidity's external and private visibility modifiers. However, you can define functions that are accessible only by certain modules, known as "friends".

  • public entry: Accessible internally, by other modules, and externally as Solidity's public.
  • public: Can be accessed internally and by other modules, but not externally.
  • public(friend): Accessible internally and by friend modules.
  • No modifier: Can be invoked only internally, akin to Solidity's internal.

address module_address {
module example {
friend module_address::example_friend;
public entry fun public_entry_function() { /* ... */ }
public fun public_fun() { /* ... */ }
public(friend) fun public_friend_fun() { /* ... */ }
fun internal_fun() { /* ... */ }
}
module example_friend {
fun calls_public_friend_fun() {
module_address::example::public_friend_fun(); // Success
}
}
module example_not_friend {
fun calls_public_friend_fun() {
module_address::example::public_friend_fun();
// Compile error: 'public_friend_fun' can only be called from
// a 'friend' of module 'module_address::example'
}
}
}