nanffi v0.0.2

Native Abstractions for Node.js

nanffi is a Node.js addon for loading and calling dynamic libraries using pure JavaScript. It can be used to create bindings to native libraries without writing any C++ code.

It also simplifies the augmentation of node.js with C code as it takes care of handling the translation of types across JavaScript and C, which can add reams of boilerplate code to your otherwise simple C.

WARNING: nanffi assumes you know what you're doing. You can pretty easily create situations where you will segfault the interpreter and unless you've got C debugger skills, you probably won't know what's going on.

Example

const nanffi = require('nanffi');
const libm = nanffi.ffi('libm');
libm.ceil(1.5); // 2

For a more detailed introduction, see the node-ffi tutorial page.

Requirements

• Linux, OS X, Windows, or Solaris.
• libffi comes bundled with node-ffi; it does not need to be installed on your system.
• The current version is tested to run on node v0.6, v0.8, v0.9 and v0.10.

Installation

Make sure you've installed all the necessary build tools for your platform, then invoke:

npm install nanffi

Usage example

Source Install / Manual Compilation

To compile from source it's easiest to use node-gyp:

npm install -g node-gyp

Now you can compile nanffi:

npm run configure
npm run build-gyp

V8 and 64-bit Types

Internally, V8 stores integers that will fit into a 32-bit space in a 32-bit integer, and those that fall outside of this get put into double-precision floating point numbers. This is problematic because FP numbers are imprecise. To get around this, the methods in node-ffi that deal with 64-bit integers return strings and can accept strings as parameters.

Call Overhead

There is non-trivial overhead associated with FFI calls. Comparing a hard-coded binding version of strtoul() to an FFI version of strtoul() shows that the native hard-coded binding is orders of magnitude faster. So don't just use the C version of a function just because it's faster. There's a significant cost in FFI calls, so make them worth it.