I have this working fine from Linux command line:
wkhtmltopdf entry.html output.pdf
But the following doesn't work from PHP code:
exec ('wkhtmltopdf entry.html output.pdf');
Interesting, I've googled and a lot of non-checked solutions and with no explanation why this is a problem. Thanks if you have the good ones.
had the same problem and i don't think anyone else should waste > 3 hours:
the solution is here: wkhtmltopdf error in apache log
you just have to install xvfp "to emulate a x-environment"
exec("xvfb-run -a wkhtmltopdf test.html output.pdf")