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CFunction wraps a raw C function pointer as a callable TypeScript function.

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Example

import ffi from 'liblibrary.so';
import { CFunction, FFIType } from 'arkffi';

const handle = ffi.load('libffi_target.so');
const ptr = ffi.getSymbolPtr(handle, 'add');

const add = CFunction({
  args: [FFIType.double, FFIType.double],
  returns: FFIType.double,
  ptr: ptr,
});

add(2.0, 3.0); // → 5.0
add.close();
ffi.close(handle);

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Syntax

function CFunction(def: {
  args: string[];
  returns: string;
  ptr: number;
}): {
  (...args: any[]): number;
  close(): void;
};

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Parameters

ParameterTypeDescription
def.argsstring[]C function argument type codes. Supports FFIType.callback (auto-extracts .ptr from JSCallback)
def.returnsstringC function return type code
def.ptrnumberRaw function pointer address

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Callback Type Arguments

When an argument type is FFIType.callback ('k'), the JSCallback instance is automatically unwrapped to its .ptr: 
let fn = CFunction({
  args: [FFIType.callback, FFIType.int32],
  returns: FFIType.int32,
  ptr: applyPtr,
});
fn(cb, 21); // cb.ptr is automatically used as the first argument

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Obtaining Pointers

Use ffi.getSymbolPtr(handle, name): 
const handle = ffi.load('lib.so');
const ptr = ffi.getSymbolPtr(handle, 'calculate');
const fn = CFunction({ args: ['i', 'd'], returns: 'd', ptr });
fn(42, 3.14);
fn.close();
ffi.close(handle);