Where can i find help files or documentation for commands like \@startsection for LaTeX

Question

I can't find official documentation for this command, help please! i look already in:

1. latex wikibook
2. Latex: Structured document for TEX, 2008
3. beginLatex...a book that comes with ProTex
4. in the files that comes with miktex in the folder "doc"

and google..... i found a lot of sites that show examples, discutions about it but i want the official help or document

Answer 1

See This discussion on the texhax mailing list for where to find the definition in the LaTeX distribution This link (PDF) has some documentation about it.

Answer 2

It’s not a LaTeX command per se (which is why it’s not well documented), but a TeX macro that’s defined in the implementation of LaTeX’s kernel. @Concerned has a good answer, but you can also explore macros in LaTeX’s interactive mode:

~$ latex
**\makeatletter
*\show\@startsection
> \@startsection=macro:
#1#2#3#4#5#6->\if@noskipsec \leavevmode \fi \par \@tempskipa #4\relax
\@afterindenttrue \ifdim \@tempskipa <\z@ \@tempskipa -\@tempskipa \@afterindentfalse \fi
\if@nobreak \everypar {}\else \addpenalty \@secpenalty \addvspace \@tempskipa \fi
\@ifstar {\@ssect {#3}{#4}{#5}{#6}}{\@dblarg {\@sect {#1}{#2}{#3}{#4}{#5}{#6}}}.

Answer 3

A lot of LaTex's internals can be mastered only by using the source, but have a look at LaTeX 2e for Class and Package Writers.