NOTE: Deprecation of the technologies described here has been announced for platforms other than ChromeOS.
Please visit our migration guide for details.

Download the Native Client SDK

This page provides an overview of the Native Client SDK, and instructions for downloading and installing the SDK.

Download SDK Zip File

Overview

The Native Client SDK includes:

Support for multiple Pepper versions to compile for specific minimum versions of Chrome.
Update utility to download new bundles and updates to existing bundles.
Toolchains to compile for Portable Native Client (PNaCl), traditional Native Client (NaCl), and for compiling architecture-specific Native Client applications with glibc.
Examples Including C or C++ source files and header files illustrating how to use NaCl and Pepper, and Makefiles to build the example with each of the toolchains.
Tools for validating Native Client modules and running modules from the command line.

Follow the steps below to download and install the Native Client SDK.

Prerequisites

Python 2.7

Make sure that the Python executable is in your PATH variable. Python 3.x is not yet supported.

On Mac and Linux, Python is likely preinstalled. Run the command python -V in a terminal window, and make sure that the version you have is 2.7.x.
On Windows, you may need to install Python. Go to https://www.python.org/ download/ and select the latest 2.x version. In addition, be sure to add the Python directory (for example, C:\python27) to the PATH environment variable. Run python -V from a command line to verify that you properly configured the PATH variable.

Make

On the Mac, you need to install make on your system before you can build and run the examples in the SDK. One easy way to get make, along with several other useful tools, is to install Xcode Developer Tools. After installing Xcode, go to the XCode menu, open the Preferences dialog box then select Downloads and Components. Verify that Command Line Tools are installed.
On Windows, the Native Client SDK includes a copy of GNU Make.

Platforms

Native Client supports several operating systems, including Windows, Linux, OSX, and ChromeOS. It supports several architectures including on x86-32, x86-64, ARM, and MIPS.

Versions

Chrome is released on a six week cycle, and developer versions of Chrome are pushed to the public beta channel three weeks before each release. As with any software, each release of Chrome may include changes to Native Client and the Pepper interfaces that may require modification to existing applications. However, modules compiled for one version of Pepper/Chrome should work with subsequent versions of Pepper/Chrome. The SDK includes multiple versions of the Pepper APIs to help developers make adjustments to API changes and take advantage of new features: stable, beta and dev.

Installing the SDK

Downloading and Unzipping

Download the SDK update zip file.
Unzip the file:
- On Mac/Linux, run the command unzip nacl_sdk.zip in a terminal window.
- On Windows, right-click on the .zip file and select “Extract All...”. A dialog box opens; enter a location and click “Extract”.
A directory is created called nacl_sdk with the following files and directories:
- naclsdk (and naclsdk.bat for Windows) — the update utility, which is the command you run to download and update bundles.
- sdk_cache — a directory with a manifest file that lists the bundles you have already downloaded.
- sdk_tools — the code run by the naclsdk command.

Installing the stable bundle

To see the SDK bundles that are available for download, go to the nacl_sdk directory and run naclsdk with the list command. The SDK includes a separate bundle for each version of Chrome/Pepper.

On Mac/Linux:
```
$ cd nacl_sdk
$ ./naclsdk list
```
On Windows:
```
> cd nacl_sdk
> naclsdk list
```
You should see output similar to this:
```
Bundles:
 I: installed
 *: update available

  I  sdk_tools (stable)
     vs_addin (dev)
     pepper_31 (post_stable)
     pepper_32 (post_stable)
     pepper_33 (post_stable)
     pepper_34 (post_stable)
     pepper_35 (stable)
     pepper_36 (beta)
     pepper_37 (dev)
     pepper_canary (canary)
```
The sample output above shows that several bundles are available for download, and that you have already installed the latest revision of the sdk_tools bundle, which was included in the zip file. You never need to update the sdk_tools bundle. It is updated automatically (if necessary) whenever you run naclsdk.

Bundles are labeled post-stable, stable, beta, dev, or canary. These labels usually correspond to the current versions of Chrome. We recommend that you develop against a “stable” bundle, because such bundles can be used by all current Chrome users. Native Client is designed to be backward-compatible.For example, applications developed with the pepper_37 bundle can run in Chrome 37, Chrome 38, etc..
Run naclsdk with the update command to download recommended bundles, including the current “stable” bundle.

On Mac/Linux:
```
$ ./naclsdk update
```
On Windows:
```
> naclsdk update
```
By default, naclsdk only downloads bundles that are recommended, generally those that are “stable.” For example, if the current “stable” bundle is pepper_35, then the update downloads that bundle. To download the pepper_36 bundle you must ask for it explicitly:
```
$ ./naclsdk update pepper_36
```

Updating bundles

Run naclsdk with the list command. This shows you the list of available bundles and verifies which bundles you have installed.

On Mac/Linux:

$ ./naclsdk list

On Windows:

> naclsdk list

An asterisk (*) next to a bundle indicates that there is an update available it. For example:

Bundles:
 I: installed
 *: update available

  I  sdk_tools (stable)
     vs_addin (dev)
     pepper_31 (post_stable)
     pepper_32 (post_stable)
     pepper_33 (post_stable)
     pepper_34 (post_stable)
  I* pepper_35 (stable)
     pepper_36 (beta)
     pepper_37 (dev)
     pepper_canary (canary)

If you run naclsdk update now, it warns you with a message similar to this:

WARNING: pepper_35 already exists, but has an update available. Run update
with the --force option to overwrite the existing directory. Warning: This
will overwrite any modifications you have made within this directory.

To download and install the new bundle, run:

On Mac/Linux:
```
$ ./naclsdk update --force
```
On Windows:
```
> naclsdk update --force
```

Help with the `naclsdk` utility

For more information about the naclsdk utility, run:

On Mac/Linux:
```
$ ./naclsdk help
```
On Windows:
```
> naclsdk help
```

Next steps

Browse the Release Notes for important information about the SDK and new bundles.
If you’re just starting with Native Client, we recommend reading the Technical Overview and walking through the Getting Started Tutorial.
If you’d rather dive in, see Building Native Client Modules.