Post

Caliban Darklock
@darklock.com

Early in my career I was called on to figure out what the hell was wrong with a FORTRAN program which had worked just fine for years, but when a contractor updated some formulas, it stopped working.

This post is unavailable.

14 reposts53 likes

Caliban Darklock
@darklock.com

They reverted to a backup and it worked, but whenever they tried to update the maths -- which were also full of weird, redundant calculations -- it stopped working again. Nobody could figure it out. It made literally zero sense. They'd change a long formula to a shorter one and everything went nuts.

Caliban Darklock
@darklock.com

Being very new and inexperienced, I took a deep breath and started at the very beginning and now you have to know something fairly specific about FORTRAN. You know in modern programming languages, your variable names are NOT ALLOWED to start with a numeral? FORTRAN doesn't have that.

Caliban Darklock
@darklock.com

What this means is that just like you can have a variable named x in C++, you can have a variable named 7 in FORTRAN. Or, in this particular case, 3. Apparently, the original programmer got tired of typing pi. But instead of defining a variable named "pi" -- well. You can guess, can't you?

Caliban Darklock
@darklock.com

No, this programmer assigned the value of pi to the integer 3. So at various points in the code he would have (1 + 2) or (4 - 1) in the maths, because when he used 3 it was pi. And nobody knew this, so they went "what the fuck is this" and corrected the weird redundant shit and the whole thing broke

Richard Matley
@richardmatley.bsky.social

Who on earth thought it was a good idea to allow the use of an integer literal as a variable name!? And how the **** did the original programmer not think twice when they had to use (4 - 1)!?

Holly
@gikkt.bsky.social

I'm guessing when this code was written code reviews were not a thing. There's no way any serious programmer would have approved that.

Caliban Darklock
@darklock.com

Probably a quirk of the specific compiler. This was in the late 1980s, but the code was old and ran on an IBM 300 series mainframe, which was already ancient. I recall the problem I had to fix, but not the details of the compiler version and manufacturer.