Document Classes ⇒ What is \p@ in "\vskip 60\p@" (standard class)

[deniss]

I'm at a bit of a loss trying to find what all these weird-looking TeX primitives mean: online searches seem useless, and the LaTeX Companion doesn't really address these.

In classes.dtx file, there is a line inside the definition for \maketitle macro which reads:

Code: Select all

\vskip 60\p@

and the authors comment "the centering is set off a little by adding \vskip".

Fine, but what is "\p@"?? Just like "\z@" and "\@ne" for setting page counter - where do I get more info on these strange little commands that nobody seems to talk about?

[gmedina]

Hi,

those are examples of some TeX constants:

\newdimen\p@ \p@=1pt % this saves macro space and time
\newdimen\z@ \z@=0pt

So, \p@ represents 1pt and \z@ represents 0pt. If you want to understand TeX internals, the TeXbook is a must-have document.

[deniss]

Many thanks - I will definitely get the TeXbook then. I always figured - I just want to use LaTeX, so it's probably an overkill! But I like being able to understand all the internal code in classes.dtx and such when I try to design something of my own.