# Usage of the \dimexpr command

I have MiKTeX 2.3 and its version of e-TeX does not support `\dimexpr` command. I do not want to update this MiKTeX now and wonder, is it possible to define the `\dimexpr` command, probably with use of `calc` package?

• e-TeX included `\dimexpr` from the start, so if you have e-TeX you should have `\dimexpr`. Have you tried running for example `elatex` rather than `latex` to ensure the extensions are enabled (used to be necessary)? – Joseph Wright Nov 10 '13 at 8:25
• Great thank! elatex.exe and pdfelatex.exe does my job. The only question. Usual – maximav Nov 10 '13 at 9:28

No, it is not possible to define it yourself but probably you do not need to anyway. Th `\dimexpr` primitive is provided by e-TeX, and since it is a primitive ('build in') it cannot be properly simulated by a macro. However, e-TeX has been around for many years. Older TeX systems used to require you to explicitly ask for e-TeX, so using `etex`, `elatex`, `pdfelatex`, etc. Thus you should try inserting an '`e`' into whichever command you currently use to run TeX: I would guess you use either `latex` or `pdflatex`, so try `elatex` or `pdfelatex` as a replacement.
• @maximav It's not obsolete. As the e-TeX extensions are useful and indeed expected in LaTeX nowadays, both MiKTeX and TeX Live decided some years ago that the extensions would always be available. So with say MiKTeX 2.9, `latex` will have the e-TeX extensions and you no longer need `elatex`, i.e. users don't need to know about this. – Joseph Wright Nov 10 '13 at 9:52
• @maximav The standard LaTeX is LaTeX2e, which was taken over by the current team in 1992 from Leslie. LaTeX2e was released in 1994 to replace 2.09. The current `latex.ltx` doesn't require e-TeX (if you read the code) but the team did decide in the early 2000s that future 'core' developments would assume e-TeX availability. – Joseph Wright Nov 10 '13 at 10:22