fatal error: pybind11/pybind11.h: No such file or directory

[chadgh]

I tried following the example in the README and got the following error:

/tmp/tmp826vncgj/somecode.cpp:2:36: fatal error: pybind11/pybind11.h: No such file or directory
     #include <pybind11/pybind11.h>

[tbenthompson]

This is a problem with the installation. The pybind11 dependency isn't being found. It's hard to easily say what the problem is.

Some quick questions:

1. Did you use pip to install?
2. Operating system?
3. Python version?
4. Virtualenv? Conda environment? Anything like that?

Would you be willing to run these lines and then list the files in the folders that are output for me?

>>> import pybind11
>>> pybind11.get_include()
'/usr/local/include/python2.7'
>>> pybind11.get_include(True)
'/home/tbent/.local/include/python2.7'

[chadgh]

1. Yes I used pip to install
2. Arch Linux
3. Python 3.5.1
4. Virtualenv

>>> import pybind11
>>> pybind11.get_include()
'/home/chadgh/.pyenv/versions/3.5.1/include/python3.5m'
>>> pybind11.get_include(True)
'/home/chadgh/.local/include/python3.5m'

So maybe 3.5.1 is not supported?

[tbenthompson]

I use 3.5 for development, so that's not it.

Could you list the files in these folders?
/home/chadgh/.pyenv/versions/3.5.1/include/python3.5m/pybind11
/home/chadgh/.local/include/python3.5m/pybind11

[chadgh]

Those paths don't exist. I have /home/chadgh/.pyenv/versions/3.5.1/include/python3.5m/ but no pybind11 in there. And I have up to /home/chadgh/.local/ but no include.

I also did a search (using the find command) at those levels and didn't find anything called pybind11.

[chadgh]

In the virtualenvironment there is ./lib/python3.5/site-packages/pybind11 and ./include/site/python3.5/pybind11

[tbenthompson]

Want to list the files in ./include/site/python3.5/pybind11? I think pybind11 is getting confused about where it installed itself!

[chadgh]

Sure

attr.h
cast.h
common.h
complex.h
descr.h
functional.h
numpy.h
operators.h
pybind11.h
pytypes.h
stl.h
typeid.h

[tbenthompson]

Okay. So, it seems that pybind11 package installed the headers in ./include/site/python3.5 but pybind11.get_include(), which is supposed to return that directory, instead returns /home/chadgh/.pyenv/versions/3.5.1/include/python3.5m/. This is a problem with the pybind11 package.

Wenzel Jakob, who is the maintainer of that project, is usually pretty responsive. Would you be up for opening an issue there?

In the meantime, you can hack things to work properly by opening ./lib/python3.5/site-packages/pybind11/__init__.py and changing

return os.path.dirname(
            locations.distutils_scheme('pybind11', *args, **kwargs)['headers'])

to just have the hardcoded path where the pybind11/pybind11.h file is: In your case YOURVIRTUALENVPATHNAME/include/site.

[chadgh]

Hmm, @tbenthompson your suggestion didn't seem to work I replace the line you specified with:

return '/home/chadgh/.virtualenvs/tmp-2ea8e0bcd287cca/include/site/python3.5/pybind11'

And am getting the same error. I've confirmed that that is the location of the directory with all of the .h files.

Also, according to @wjakob this looks like it might be a pip issue. pypa/pip#3696

[chadgh]

I did just confirm that if I avoid the virtualenv, the example works.

[tbenthompson]

Glad we got to the root of the problem. Thanks for reporting this.

With your hack fix, the pybind11 at the end of the line is the problem. It should be:

return '/home/chadgh/.virtualenvs/tmp-2ea8e0bcd287cca/include/site/python3.5'

[timbicker]

I have the same problem with python 3.7.