Archive for June, 2014

Checking Symbols GCC and Clang

Friday, June 20th, 2014

Just a short one.


Gives you list of all symbols defined by compilers. It’s interesting, that you have to feed it something (anything blank) to get this output though. /dev/null, or pipe in a blank echo (echo “” | gcc -dM -E -), etc.

Works with NaCl (pnacl-clang), Emscripten (emcc), and pretty much every GCC toolchain known to man.

Setting up NaCL and SDL (on a fresh Ubuntu)

Friday, June 6th, 2014

Some notes on getting NaCl working. Of course, things didn’t work out-of-the box.

Install nacl_sdk

Grab and follow the instructions here:

i.e. download and do the following:

Install 32bit Headers

‘cmon, everybody runs 64bit Linux these days (in my case Ubuntu 14.04 64bit). You need the 32bit libraries for anything to build though.


Follow Tutorial

‘make serve’ will now work.

Test2 probably wont run though. I haven’t checked, but I think it may not be a pnacl file (pnacl is necessary to run in a stock Chrome).

EDIT: The problem with Test2 is that newlib is the first Toolchain. If you modify the Makefile by making pnacl the first VALID_TOOLCHAINS (or commenting out the line entirely), and change index.html, the data-tools attribute of the body tag, make pnacl first, it will work correctly.

Now, lets see how far we get compiling SDL NaCL.

Set Environment Variables for SDL


Do something like the following.

‘readlink -f’ takes a path and converts it in to an absolute path (by following symlinks, ..’s, etc). If you’re on Windows, substitute it for the absolute path to your pepper directory. Mine is /home/mike/Work/Build/nacl_sdk/pepper_35

And of course, edit your pepper version accordingly (35 or whatever).

Build SDL2 in NaCL mode

SDL must be built outside the main SDL directory. I like to call my SDL directory “SDL2”, and do builds in directories like “SDLBuild”. I invoke my build like follows:

Notably, I’m putting the output (make install) inside the SDL subdirectory of the pepper SDK folder.

The Makefile

EDIT: For the makefile to work, I had to make a few changes. Here is the full modified makefile.

The changes are lines 19 and 20. Line 22 is new, as are lines 67 and 68. The last 2 lines are a hack to make “make serve” work the same as it does in the NaCl demos.

Here’s a diff.

For reference, my old notes (before I got it working by changing the makefile):

Okay, this didn’t actually work. I’m not sure exactly how it’s supposed to be configured, but it’s not configured correctly. It should only be used as a reference. Some other notes of things I had to do to get it to work:

naclbuild script

Alternatively, once the environment is set correctly (I think just NACL_SDK_ROOT) it’ll work. In the ‘build-tools’ folder is a script ‘naclbuild’. Run that, and it’ll put some output in the Build folder. Once it finishes, it gives you a string to copy+paste in to your shell. Do it.

Vine Videos:,

Currently works on Desktop Chrome, and Chrome OS. Will not work on Android (yet).