Bug#311424: checking for write18

[Ralf Stubner <ralf.stubner@physik.uni-erlangen.de>]

Frank Küster wrote:
> Norbert Preining <preining@logic.at> wrote:
>
>> From the bug reports last entry:
>> I have realized the cause of the problem. To enable pdf creation on the
>> fly, the `\write18' has to be enabled via the command line option:
>> -shell-escape of pdflatex
>> (example: pdflatex -shell-escape test.tex) or via the configuration file
>> `texmf.cnf': (shell_escape = 1) as it is stated in the epstopdf.sty
>> file.
>> However one should not expect the user to dig into the sty files.

Documentation inside the sty file is not that uncommon. Main problem is
that it doesn't work together with texdoc.

>> Therefor I suggest an appropriate error message, when the epstopdf
>> packages is used in latex documents, but `\write18' is disabled. In
>> addition an example of how to enable it (example: pdflatex -shell-escape
>> test.tex) would be very helpful.
> 
> Does anybody on the list know how to check whether \write18 is enabled
> in a TeX document?

I remember vaguely some discussion on (de.)comp.text.tex that it is
difficult/almost impossible, especially in a platform independent way.
However, I didn't find anything on groups.google.com yet. One could ask
upstream to add an uncoditional message telling people to enable
write18/shell escapes.

cheerio
ralf