Re: [pretest] regression in pdftex

Karl and all, hello.

On 17 Feb 2026, at 23:31, Karl Berry wrote:

>     different compilers initialised it differently by default.
>
> Or left it uninitialized, making the value is effectively random. That's
> what "normal" compilers do,

I'm sure we could bicker most agreeably about what counts as ‘normal’ here!

> not blatantly force initialization to
> zero. I'm surprised to hear that clang does that.

I see it's controlled by an option -ftrivial-auto-var-init in the intimidatingly long list of clang compiler options, and it appears that the default value of it has changed more than once (and I see there was at one time a clang option -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang), so one gets the sense that opinions differ about whether this is a Good Thing or not.

I appreciate it would be useful in production builds, so that the binary at least produces _consistent_ misbehaviour, but the downside in development builds is of course hiding goofs.

Best wishes,

Norman


[1] https://clang.llvm.org/docs/ClangCommandLineReference.html

-- 
Norman Gray  :  https://nxg.me.uk