[texhax] latex --version = pdfTeX ... ?

[Daniel Greenhoe]

That is very helpful information---thank you very much for posting it.

I also thanked David two days or so ago; but looking back, it appears
I only sent the thank you email to David, and not to the texhax
mailing list as well. Many apologies :(

Dan

On Sun, Nov 15, 2015 at 12:20 AM, Karl Berry <karl at freefriends.org> wrote:
>     Could something that begins with "pdfTeX" really be the version number
>     of a latex.exe program? Is latex.exe just a special configuration of
>     pdftex?
>
> Yes.  LaTeX is a so-called "format" (collection of macros), not a
> separate executable in itself.  http://tug.org/levels.html discusses
> such things briefly.  (tug.org is inaccessible briefly due to network
> infrastructure work, but hopefully will be back by the time you read this.)
>
> pdfTeX can output DVI, and does so by default when invoked as
> "latex", etc.
>
>     Is there any way to read the latex and/or dvipdfmx version numbers
>     at compile time and pass the string(s) to the metadata of the final
>     pdf file?
>
> David mentioned \fmtversion for the real LaTeX version.
>
> You can get the "engine" (pdftex) version with, most descriptive,
> \pdftexbanner.  Assuming you are using "latex".
>
> There's no (safe) way to get the dvipdfmx version number from within
> TeX.  You'd need to extract it with something like
>   dvipdfmx --version | sed 1q >fmxver.txt
> and then read that external file.
>
> Good luck.  Hope this helps,
> Karl