问题
I am working on a simple piece of code that runs a Python function from a C/C++ application. In order to do this I set the PYTHONPATH and run initialize as follows:
Py_SetPythonHome(\"../Python27\");
Py_InitializeEx(0);
Then I import my module and run my function. It works great.
I am now attempting to build an installer for my colleagues to run my code. I want to minimize the number of files I need to include in this installer, for obvious reasons.
Googling around the subject tells me that I should be able to include the files \"Python27.lib\" and \"Python27.dll\", then zip the \"DLLs\" and \"Lib\" folders and include them. However, when I attempt this, Py_Initialize fails.
A quick examination of what is causing this failure shows that Py_Initialize appears to depend upon a number of .pyc files in the Lib folder including (but not limited to warnings.pyc, _abcoll.pyc, _future_.pyc and the contents of the \"encodings\" folder.
I cannot understand why this would be. Any advice?
回答1:
At the beginning, I wanted to say that there's no module required (at least no non-builtin one) for Py_InitializeEx, so the only requirement was python27.dll (btw: python27.lib is not required, unless your colleagues want to link something against it - but that wouldn't be very easy w/o Python's Include dir). I had this code (BTW: I am using Python 2.7.10 that I built using VStudio 10 (2010)):
#include <stdio.h>
#include <conio.h>
#include <Python.h>
int main() {
int i = 0;
char *pyCode =
"s = \"abc\"\n"
"print s, 1234";
Py_InitializeEx(0);
i = PyRun_SimpleString(pyCode);
Py_Finalize();
printf("PyRun_SimpleString returned: %d\nPress a key to exit...\n", i);
_getch();
return 0;
}
It built fine, it ran OK from VStudio, and from the command line (after copying the .dll in its folder). But then I copied the .exe and .dll to another computer and when running, bang!!!
ImportError: No module named site
Considering that:
- I have no PYTHON* env vars set in neither of the consoles on the 2 machines where I ran the .exe (with different results)
- On both machines the Python installation is on the same path (I previously (years ago) modified it on the machine that doesn't work)
I don't know why it doesn't behave the same (one thing that I haven't check is that there might be some registry key on the machine that works?).
Note: site is a (.py(c)) module located under %PYTHON_INSTALL_DIR%\Lib.
Then, I browsed Python's source code and I came across this (file: pythonrun.c, line: 269, function Py_InitializeEx or pythonrun.c:269: Py_InitializeEx - this is how I'm going to refer a point in the source code):
if (!Py_NoSiteFlag)
initsite(); /* Module site */
while in pythonrun.c:727: initsite:
m = PyImport_ImportModule("site");
which is pretty obvious (Py_NoSiteFlag is 0).
Then I noticed that Py_NoSiteFlag is declared as extern __declspec(dllexport) ([MS.Docs]: Using extern to Specify Linkage, [MS.Docs]: dllexport, dllimport), so I modified my code to:
#include <stdio.h>
#include <conio.h>
#include <Python.h>
extern __declspec(dllimport) int Py_NoSiteFlag;
int main() {
int i = 0;
char *pyCode =
"s = \"abc\"\n"
"print s, 1234";
Py_NoSiteFlag = 1;
Py_InitializeEx(0);
i = PyRun_SimpleString(pyCode);
Py_Finalize();
printf("PyRun_SimpleString returned: %d\nPress a key to exit...\n", i);
_getch();
return 0;
}
and it works! Yay!
So, at this point only the .dll is required in order to run a piece of code. But I imagine that your code is "a little bit" more complex than that (it has imports ([Python 2.Docs]: The import statement). To solve the import problem, you can use this nice module: [Python 2.Docs]: modulefinder - Find modules used by a script (part of Python 2.7's standard modules). To make use of it:
- Save the code that you execute from C in a .py file
- Run modulefinder against it
Here's an example for my code (pyCode contents in my C program, saved in a file).
code.py:
s = "abc"
print s, 1234
Running:
%PYTHON_INSTALL_DIR%\python -m modulefinder code.py
yields:
Name File ---- ---- m __main__ code.py
But, if I add an import os (which is a pretty common module) statement in the file, the above command yields:
Name File ---- ---- m StringIO %PYTHON_INSTALL_DIR%\lib\StringIO.py m UserDict %PYTHON_INSTALL_DIR%\lib\UserDict.py m __builtin__ m __future__ %PYTHON_INSTALL_DIR%\lib\__future__.py m __main__ a.py m _abcoll %PYTHON_INSTALL_DIR%\lib\_abcoll.py m _codecs m _collections m _functools m _hashlib %PYTHON_INSTALL_DIR%\DLLs\_hashlib.pyd m _heapq m _io m _locale m _random m _sre m _struct m _subprocess m _threading_local %PYTHON_INSTALL_DIR%\lib\_threading_local.py m _warnings m _weakref m _weakrefset %PYTHON_INSTALL_DIR%\lib\_weakrefset.py m abc %PYTHON_INSTALL_DIR%\lib\abc.py m array m atexit %PYTHON_INSTALL_DIR%\lib\atexit.py m bdb %PYTHON_INSTALL_DIR%\lib\bdb.py m binascii m cPickle m cStringIO m cmd %PYTHON_INSTALL_DIR%\lib\cmd.py m codecs %PYTHON_INSTALL_DIR%\lib\codecs.py m collections %PYTHON_INSTALL_DIR%\lib\collections.py m copy %PYTHON_INSTALL_DIR%\lib\copy.py m copy_reg %PYTHON_INSTALL_DIR%\lib\copy_reg.py m difflib %PYTHON_INSTALL_DIR%\lib\difflib.py m dis %PYTHON_INSTALL_DIR%\lib\dis.py m doctest %PYTHON_INSTALL_DIR%\lib\doctest.py m dummy_thread %PYTHON_INSTALL_DIR%\lib\dummy_thread.py P encodings %PYTHON_INSTALL_DIR%\lib\encodings\__init__.py m encodings.aliases %PYTHON_INSTALL_DIR%\lib\encodings\aliases.py m errno m exceptions m fnmatch %PYTHON_INSTALL_DIR%\lib\fnmatch.py m functools %PYTHON_INSTALL_DIR%\lib\functools.py m gc m genericpath %PYTHON_INSTALL_DIR%\lib\genericpath.py m getopt %PYTHON_INSTALL_DIR%\lib\getopt.py m gettext %PYTHON_INSTALL_DIR%\lib\gettext.py m hashlib %PYTHON_INSTALL_DIR%\lib\hashlib.py m heapq %PYTHON_INSTALL_DIR%\lib\heapq.py m imp m inspect %PYTHON_INSTALL_DIR%\lib\inspect.py m io %PYTHON_INSTALL_DIR%\lib\io.py m itertools m keyword %PYTHON_INSTALL_DIR%\lib\keyword.py m linecache %PYTHON_INSTALL_DIR%\lib\linecache.py m locale %PYTHON_INSTALL_DIR%\lib\locale.py P logging %PYTHON_INSTALL_DIR%\lib\logging\__init__.py m marshal m math m msvcrt m nt m ntpath %PYTHON_INSTALL_DIR%\lib\ntpath.py m opcode %PYTHON_INSTALL_DIR%\lib\opcode.py m operator m optparse %PYTHON_INSTALL_DIR%\lib\optparse.py m os %PYTHON_INSTALL_DIR%\lib\os.py m os2emxpath %PYTHON_INSTALL_DIR%\lib\os2emxpath.py m pdb %PYTHON_INSTALL_DIR%\lib\pdb.py m pickle %PYTHON_INSTALL_DIR%\lib\pickle.py m posixpath %PYTHON_INSTALL_DIR%\lib\posixpath.py m pprint %PYTHON_INSTALL_DIR%\lib\pprint.py m random %PYTHON_INSTALL_DIR%\lib\random.py m re %PYTHON_INSTALL_DIR%\lib\re.py m repr %PYTHON_INSTALL_DIR%\lib\repr.py m select %PYTHON_INSTALL_DIR%\DLLs\select.pyd m shlex %PYTHON_INSTALL_DIR%\lib\shlex.py m signal m sre_compile %PYTHON_INSTALL_DIR%\lib\sre_compile.py m sre_constants %PYTHON_INSTALL_DIR%\lib\sre_constants.py m sre_parse %PYTHON_INSTALL_DIR%\lib\sre_parse.py m stat %PYTHON_INSTALL_DIR%\lib\stat.py m string %PYTHON_INSTALL_DIR%\lib\string.py m strop m struct %PYTHON_INSTALL_DIR%\lib\struct.py m subprocess %PYTHON_INSTALL_DIR%\lib\subprocess.py m sys m tempfile %PYTHON_INSTALL_DIR%\lib\tempfile.py m textwrap %PYTHON_INSTALL_DIR%\lib\textwrap.py m thread m threading %PYTHON_INSTALL_DIR%\lib\threading.py m time m token %PYTHON_INSTALL_DIR%\lib\token.py m tokenize %PYTHON_INSTALL_DIR%\lib\tokenize.py m traceback %PYTHON_INSTALL_DIR%\lib\traceback.py m types %PYTHON_INSTALL_DIR%\lib\types.py P unittest %PYTHON_INSTALL_DIR%\lib\unittest\__init__.py m unittest.case %PYTHON_INSTALL_DIR%\lib\unittest\case.py m unittest.loader %PYTHON_INSTALL_DIR%\lib\unittest\loader.py m unittest.main %PYTHON_INSTALL_DIR%\lib\unittest\main.py m unittest.result %PYTHON_INSTALL_DIR%\lib\unittest\result.py m unittest.runner %PYTHON_INSTALL_DIR%\lib\unittest\runner.py m unittest.signals %PYTHON_INSTALL_DIR%\lib\unittest\signals.py m unittest.suite %PYTHON_INSTALL_DIR%\lib\unittest\suite.py m unittest.util %PYTHON_INSTALL_DIR%\lib\unittest\util.py m warnings %PYTHON_INSTALL_DIR%\lib\warnings.py m weakref %PYTHON_INSTALL_DIR%\lib\weakref.py Missing modules: ? _emx_link imported from os ? ce imported from os ? fcntl imported from subprocess, tempfile ? org.python.core imported from copy, pickle ? os.path imported from os, shlex ? os2 imported from os ? posix imported from os ? pwd imported from posixpath ? readline imported from cmd, pdb ? riscos imported from os ? riscosenviron imported from os ? riscospath imported from os
As you can see, there is an awfully lot of modules (I modified the output a little bit, instead of the actual path I placed the %PYTHON_INSTALL_DIR% env var). In order for the Python code to work, you'll have to include all of those modules/packages in the installer.
Notes about modulefinder's output (that I've noticed while playing with it):
- It searches for modules recursively, so here is the whole module dependency tree
- It searches for import statements located in functions (so, not only the ones at module level)
- It doesn't search for dynamic imports (e.g. [Python 2.Docs]: __import__(name[, globals[, locals[, fromlist[, level]]]]))
So, looking at the modules that are required by os, I'm not sure that taking out the site import from C makes much of a difference.
IMPORTANT NOTE: To make sure your .exe works on any computer, you might consider including VStudio C Runtime Library or VCRTLib (msvcr##(#).dll: [MS.Docs]: Run-Time Library Reference) (where #s are placeholders for digits - representing VStudio version) in your installer.
来源：https://stackoverflow.com/questions/39539089/what-files-are-required-for-py-initialize-to-run