[OS X TeX] Using \usepgfplotslibrary{external}

[Herbert Schulz]

> On Aug 4, 2016, at 9:35 AM, Martin Bergren <martin.berggren at cs.umu.se> wrote:
> 
>> 
>> On 04 Aug 2016, at 16:20, Herbert Schulz <herbs at wideopenwest.com> wrote:
>> 
>>> On Aug 4, 2016, at 9:09 AM, Martin Bergren <martin.berggren at cs.umu.se> wrote:
>>> 
>>>> 
>>>> On 04 Aug 2016, at 15:57, Herbert Schulz <herbs at wideopenwest.com> wrote:
>>>> 
>>>>> On Aug 4, 2016, at 7:56 AM, Martin Bergren <martin.berggren at cs.umu.se> wrote:
>>>>> 
>>>>>> On 04 Aug 2016, at 14:52, Herbert Schulz <herbs at wideopenwest.com> wrote:
>>>>>> 
>>>>>>> On Aug 4, 2016, at 7:22 AM, Martin Bergren <martin.berggren at cs.umu.se> wrote:
>>>>>>> 
>>>>>>> I would like to be able to use
>>>>>>> 
>>>>>>> \usepgfplotslibrary{external}
>>>>>>> 
>>>>>>> for pgfplots, which apparently should be able to store the pgfplots or tikz figures as pdfs to shorten latexing time. The problem seem to be write18. 
>>>>>>> Is there a way around it?
>>>>>>> 
>>>>>>> Cheers,
>>>>>>> 
>>>>>>> 
>>>>>>> Martin Berggren
>>>>>> 
>>>>>> Howdy,
>>>>>> 
>>>>>> Assuming you are using TeXShop:
>>>>>> 
>>>>>> One thing you can use is the sepdflatexmk engine. This is set up to use latexmk so that all processing through bibtex/biber and makeindex is taken care of if necessary and the pdflatex has the --shell-escape flag set. To use it simply place the line
>>>>>> 
>>>>>> % !TEX TS-program = sepdflatexmk
>>>>>> 
>>>>>> at the top of your file and then typeset the document by simply using Typeset->Typeset (Cmd-T).
>>>>>> 
>>>>>> 
>>>>> 
>>>>> But this is not a bibtex/biber and makeindex issue. This is about pgfplots,  which I think is running (in my case) lualatex in the background to produce the plots.
>>>>> 
>>>>> Cheers,
>>>>> 
>>>>> Martin Berggren
>>>> 
>>>> Howdy,
>>>> 
>>>> If it's really using lualatex you need to somehow have it load the luatex85 package and the shellesc package under lualatex. I don't know if your initial file is run under lualatex but you might try to include
>>>> 
>>>> \ifx\directlua\@undefined
>>>> \else
>>>> \RequirePackage{luatex85}
>>>> \RequirePackage{shellesc}
>>>> \fi
>>>> 
>>>> before the \documentclass command. Otherwise you need to see how to have that included in the lualatex call.
>>>> 
>>>> I think tikz-fct uses gnuplot and, assuming you have gnuplot in your PATH, using the shell escape provided by the sepdflatexmk engine should do the job.
>>> 
>>> No, luatex is not the issue (same problem with pdftex), and I don’t think this is a gnuplot issue either. The error I get is the following:
>>> 
>>> Package tikz Error: Sorry, the system call 'lualatex -halt-on-error -interact
>>> ion=batchmode -jobname "portoptreport1-figure0" "\def\tikzexternalrealjob{porto
>>> ptreport1}\input{portoptreport1}"' did NOT result in a usable output file 'port
>>> optreport1-figure0' (expected one of .pdf:.jpg:.jpeg:.png:). Please verify that
>>> you have enabled system calls. For pdflatex, this is 'pdflatex -shell-escape'.
>>> Sometimes it is also named 'write 18' or something like that. Or maybe the com
>>> mand simply failed? Error messages can be found in 'portoptreport1-figure0.log'
>>> . If you continue now, I'll try to typeset the picture. 
>>> 
>>> That’s why I in my first post said that it seems to be a write18 issue. To me it seems like lualatex (or pdflatex)  is supposed to run as a system command to produce the picture files. 
>>> 
>>> (The point with the  \usepgfplotslibrary{external} command is that tikz and pgfplot should not need to interpret the figures each time but instead produce a pdf-file, save it to a subdirectory, and use that in order to speed up the process).
>>> 
>>> Cheers,
>>> 
>>> Martin Berggren
>> 
>> Howdy,
>> 
>> Pretty confusing message. It says it can't get output from a lulatex command (which doesn't contain --shell-escape --- and even then it would need to include those packages since luatex in TL2016 does system calls through a different mechanism, hence the addition of the luatex85 and shellesc packages) and then talks about pdflatex --shell-escape. The sepdflatex engine in TeXShop does call pdflatex with --shell-escape but has no control over any internal call to lualatex.
>> 
>> I'd suggest putting the question on Stack Exchange, <http://tex.stackexchange.com>, which is monitored by many experienced folks.
> 
> 
> As I understand it, it is only a few system commands that are allowed through \write18{}, namely those explicitly listed in /usr/local/texlive/2016/texmf-dist/web2c/texmf.cnf, which is 
> 
> shell_escape_commands = \
> bibtex,bibtex8,\
> extractbb,\
> gregorio,\
> kpsewhich,\
> makeindex,\
> mpost,\
> repstopdf,\
>  
> I tried to set shell_escape = a in my local texmf.cnf file, but that does not work either. It is regarded a security issue, it seems. 
> 
> Cheers,  
> 
> Martin Berggren

Howdy,

Not quite... The restricted shell escape list allows pdftex to execute the programs on that list even without --shell-escape being set. If you do set --shell-escape it allows pdftex to execute anything you ask for and is therefore not secure.

Part of the problem is that luatex in TL2016 no longer uses \write18 to execute external commands even if allowed to using --shell-escape. That is why requiring the luatex85 and shellesc packages in lualatex is necessary to simulate the use of \write18.

Good Luck,

Herb Schulz
(herbs at wideopenwest dot com)