On Tue, Feb 02, 2016 at 09:41:19PM +0100, Ludovic Courtès wrote: > Could you give it a try and refine as needed? :-) I altered your example as shown in the attached patch. It causes some tests related to timestamps to fail, so I disabled them in a very crude way. The final patch should address those tests more carefully. But, the patch doesn't seem to have the desired effect so I'm asking for help! Here is how I tested the patch: I build python-3 with it, and then `export SOURCE_DATE_EPOCH=1` and enter the resulting Python shell. I manually define the '_w_long' function used by the patched function. Then: print (_w_long(locale.atoi(os.getenv('SOURCE_DATE_EPOCH')))) b'\x01\x00\x00\x00' But, when I leave the Python shell and issue `python3 -m compileall helloworld.py`, the timestamps are present in the compiled bytecode. I can watch the clock "tick" by doing this repeatedly: $ touch helloworld.py && rm -r __pycache__ && \ python3 -m compileall helloworld.py && \ hexdump __pycache__/helloworld.cpython-34.pyc | head -n1 I'm not much of a Python programmer, so I'm stumped.