Determine within LaTeX how many times latexmk have run

Question

Backround

So I've gathered that latexmk runs pdflatex until "all files are up to date".

Problem and motivation

Say that I have some dynamic content that should only be run once. By dynamic I mean a content that changes every time you run it.

In principle: assume you could have a command \randomNumber which change every time it is run, giving you a random number, and thus causes latexmk to run forever.

A real world example would be compiling Rnw-files that have randomness in them.

\immediate\write18{compileMyKnitr}\input{myRnw.tex}

Question

Is there

A latex command that will tell me how many runs latexmk have done

and/or

Some fancy logic that can be done with e.g. the .aux file to determine whether this is the first run or not?

Ideally \ifFirstRun{\doSomething} or \LatexmkRunOnce{\doSomething}

a smilar question was answered here. a) you can use the aux file to save and restore number of runs b) i think your 2 nd point is good in this situation. — touhami, Mar 24 '18 at 15:53
You can use \IfFileExists{\jobname.aux}{yes}{no} in the preamble as the aux file is generated on the first run, at \begin{document} so by definition it's not there on teh first run in the preamble — David Carlisle, Mar 24 '18 at 16:53
Was actually considering writing Missing \begin{document}, but refrained, haha. — Andreas Storvik Strauman, Mar 24 '18 at 17:50

score 4 · Answer 1 · edited Mar 26 '18 at 16:17

4

Here is a solution. Deleting the .aux means restart the counter, (even if no counter is used here).

1)

\documentclass{article}

\providecommand\runsnumber{1}
\makeatletter
\AtEndDocument{%
    \write\@auxout{%
        \xdef\string\runsnumber{\the\numexpr\runsnumber+1\relax}}}
\makeatother
\begin{document}
foo

\runsnumber
\end{document}

2)

\documentclass{article}

\makeatletter
\AtEndDocument{\write\@auxout{\gdef\string\notfirstrun{}}}
\newcommand{\iffirstrun}{%
    \@ifundefined{notfirstrun}}
\makeatother
\begin{document}
foo
\iffirstrun{yes}{no}
\end{document}

edited Mar 26 '18 at 16:17

John Collins

11,183
3
32
33

answered Mar 24 '18 at 16:13

touhami

19,520

Awesome! I will just take your word for it that it works, since I don't have the files here to test it. One question though: Why \providecommand? – Andreas Storvik Strauman Mar 24 '18 at 17:14
1

\providecommand defines the command only in first run since it is not defined yet. see here – touhami Mar 24 '18 at 17:42
1

One complication: Suppose you have already compiled the document so that the .aux file exists, you change a source file, and then compile the document again by latexmk. Because of the line in the .aux file defining \notfirstrun, the first compilation will be treated as a not-first run by the document. To overcome this, one can delete the .aux file first, as the answer points out. But it would also be possible to arrange for latexmk to fix the .aux file on the first run. I could provide suitable definition to put in a latexmkrc file. – John Collins Mar 25 '18 at 18:19
@JohnCollins good point – touhami Mar 25 '18 at 21:43
1

@AndreasStorvikStrauman this is just to see the new comment – touhami Mar 25 '18 at 21:44
@JohnCollins If you have a suitable definition that would be great!! – Andreas Storvik Strauman Mar 26 '18 at 07:05
1

@AndreasStorvikStrauman I've added a suitable definition. – John Collins Mar 26 '18 at 15:14
@JohnCollins it's better if you write a new answer. – touhami Mar 26 '18 at 15:37
@touhami Will do. Since your answer gave a correct solution and had already been accepted, it seemed better simply to improve it. – John Collins Mar 26 '18 at 16:02
Wow! You guys are amazing! Answers like these are the ones that have inspired me to be active on this site. Thank you @JohnCollins and @touhami! – Andreas Storvik Strauman Mar 26 '18 at 16:12
@AndreasStorvikStrauman your welcome :-) – touhami Mar 26 '18 at 17:13
@touhami The first example will not work with latexmk because \runsnumber keep changing every run, and thus latexmk will never be satisified! – Andreas Storvik Strauman May 07 '18 at 09:56
you can start by deleting the .aux or no? – touhami May 08 '18 at 19:48
According to lthooks documentation (page 21), one should replace in that case \AtEndDocument by \AddToHook{enddocument/afterlastpage}. – Jérôme LAURENS Sep 16 '21 at 11:54

score 4 · Accepted Answer · answered Mar 26 '18 at 16:15

There are two parts to a solution.

First is to make a .tex file that detects whether it's being compiled on the first run or not:

\documentclass{article}

\makeatletter
\AtEndDocument{\write\@auxout{\gdef\string\notfirstrun{}}}
\newcommand{\iffirstrun}{%
    \@ifundefined{notfirstrun}}
\makeatother
\begin{document}
foo
\iffirstrun{yes}{no}
\end{document}

(Note that the syntax for the use of \iffirstrun is different from that for standard \iff... constructs. That could be fixed, of course.)

This solution puts a line \gdef\notfirstrun{} in the .aux file, to flag that the next run is not the first.

However, with only that part of the solution, when latexmk is again invoked after a change in source file(s), the first actual run will not be treated as a first run by the document. This is normally not desired. One could avoid this by deleting the .aux file, which may result in a lot of extra processing (and is easy to forget). This problem is solved by the following code in a latexmkrc file:

$latex = 'internal my_latex latex %O %S';
$lualatex = 'internal my_latex lualatex %O %S';
$pdflatex = 'internal my_latex pdflatex %O %S';
$xelatex = 'internal my_latex xelatex -no-pdf %O %S';
sub my_latex {
   if ( ( -e $aux_main ) && ($pass{$rule} == 1) ) {
      print "========Remove any 'notfirstline' line from aux file\n";
      my $aux_bak = "$aux_main.bak";
      rename $aux_main, $aux_bak;
      my $auxold = new FileHandle;
      my $auxnew = new FileHandle;
      open $auxold, "<$aux_bak";
      open $auxnew, ">$aux_main";
      while (<$auxold>) {
         if ( ! /^\\gdef \\notfirstrun\{\}$/ ) { print $auxnew $_; }
      }
      close $auxold;
      close $auxnew;
  }
  return system( @_ );
}

It uses a couple of internal variables of latexmk: $aux_main and $pass{$rule}.

Determine within LaTeX how many times latexmk have run

Backround

Problem and motivation

Question

2 Answers2