Question

How can I test or check C++ code for endian-independence? It’s already implemented, I would just like to verify that it works on both little- and big-endian platforms.

I could write unit tests and run them on the target platforms, but I don’t have the hardware. Perhaps emulators?

Are there compile time checks that can be done?

Answer 1

If you have access to an x86-based Mac then you can take advantage of the fact that Mac OS X has PowerPC emulation built in as well as developer tool support for both x86 (little endian) and PowerPC (big endian). This enables you to compile and run a big and little endian executable on the same platform, e.g.

$ gcc -arch i386 foo.c -o foo_x86 # build little endian x86 executable
$ gcc -arch ppc foo.c -o foo_ppc  # build big endian PowerPC executable

Having built both big endian and little endian executables you can then run whatever unit tests you have available on both, which will catch some classes of endianness-related problems, and you can also compare any data generated by the executables (files, network packets, whatever) – this should obviously match.