> ## Documentation Index
> Fetch the complete documentation index at: https://docs.starknet.io/llms.txt
> Use this file to discover all available pages before exploring further.

# core::starknet::syscalls::library_call_syscall

Calls the requested function in any previously declared class.

## Signature

```rust theme={null}
pub extern fn library_call_syscall(class_hash: ClassHash, function_selector: felt252, calldata: Span) -> Result, Array> implicits(GasBuiltin, System) nopanic;
```

#### Arguments

* `class_hash` - The hash of the class to be used.
* `function_selector` - A selector for a function within that class.
* `calldata` - Call arguments.