capi-sig October 2009

capi-sig@python.org

4 participants
4 discussions

C integration with multithreaded Python script

by Andreas Sommer

Hope this is the right mailing list, please complain if not ;) I'm currently experimenting with the integration of Python (2.6) scripts into my application, and am using the following script for testing: *import* threading, time *def* handler(): print("a") time.sleep(0.95) print("b") t = threading.Thread(target = handler) t.start() And in C++, it's this code: Py_SetProgramName("test"); Py_Initialize(); *if*(!Py_IsInitialized()) *throw* std::exception(); PyObject *module = PyImport_AddModule("__main__"); PyObject *dict = PyModule_GetDict(module); printf("1\n"); strcpy(script, "import threading, time\n" "def handler():\n" " print(\"a\")\n" " time.sleep(0.95)\n" " print(\"b\")\n" "t = threading.Thread(target = handler)\n" "t.start()\n"); PyObject *obj = PyRun_String(script, Py_file_input, dict, dict); printf("2\n"); PyErr_Print(); Py_Finalize(); When executing, the output is 1 a2 as opposed to the expected 1 a b 2 It seems to me that when the main execution path (after t.start()) finishes, the other thread (called t) is canceled?! Adding t.join() to the end of the script gives the expected output, but isn't it possible to let PyRun_xxx wait for all remaining threads to end? I know the Python interpreter does this, but I didn't get much information from its source code (it seems to run scripts with the runpy module). Best regards

10 years, 8 months

Garbage Collection Error

by Nathan Osman

Everyone was so helpful with my last question, I think I'll ask another. I have an app that uses the Python/C api. It loads a few scripts, calls a few functions, and everything works fine. That is, until the app exits and calls Py_Finalize. Then the following error appears: (GetName is a function in one of the scripts) Exception AttributeError: "'module' object has no attribute 'GetName'" in 'garbage collection' ignored Fatal Python error: unexpected exception during garbage collection Then the app crashes. Im using Python 3.1 on Windows if that helps. Any advice would be appreciated. - George _________________________________________________________________ CDN College or University student? Get Windows 7 for only $39.99 before Jan 3! Buy it now! http://go.microsoft.com/?linkid=9691636

10 years, 8 months

Re: [capi-sig] Couple of Questions About Statically Linking the Interpreter

by Campbell Barton

There are a few ways to set this path from C before starting python setenv("PYTHONHOME", somepath, 1); or... Py_SetPythonHome(py_path_bundle_wchar); Heres a function that blender uses to setup python3.1's path, there are a few blender functions here but should still be useful. the #if0's part works too but I preferred to set the home folder directly. /* must be called before Py_Initialize */ void BPY_start_python_path(void) { char *py_path_bundle= BLI_gethome_folder("python", BLI_GETHOME_ALL); if(py_path_bundle==NULL) return; /* set the environment path */ printf("found bundled python: %s\n", py_path_bundle); #if 0 BLI_setenv("PYTHONHOME", py_path_bundle); BLI_setenv("PYTHONPATH", py_path_bundle); #endif { static wchar_t py_path_bundle_wchar[FILE_MAXDIR]; mbstowcs(py_path_bundle_wchar, py_path_bundle, FILE_MAXDIR); Py_SetPythonHome(py_path_bundle_wchar); } } On Tue, Oct 20, 2009 at 8:34 PM, Nathan Osman <george_edison55(a)hotmail.com> wrote: > Thanks for your help. So if I bundle everything in the Lib directory with > the application what function would I call to inform Python where the > modules are located before I call Py_Initialize? > > Thanks, > Nathan > >> Date: Tue, 20 Oct 2009 15:02:54 +0200 >> From: ideasman42(a)gmail.com >> To: capi-sig(a)python.org >> Subject: Re: [capi-sig] Couple of Questions About Statically Linking the >> Interpreter >> >> for python 2.x you can get away only with statically linked library, >> but then you miss modules like math, struct and os >> If you want these modules you can compile some of these into the >> library you can build python with a modified config >> >> -- quick howto -- >> edit ./Modules/Setup >> uncomment "#*shared*" around line 152 and rename to "*static*" The >> following modules are built into libpython2.5.a >> uncomment: array, math, time, operator, itertools, cStringIO, cPickle, >> zlib, _struct, _weakref, _random, binascii, collections, fcntl, spwd, >> grp, select >> -- >> >> Or you can bundle python25.zip with your application and include all >> modules in this, however youll need zlib either compiled statically or >> include the module unzipped in the dir. >> >> Blender2.49 for example in win32 has python26.zip and zlib.pyd in the >> current directory so python can extract the zip and open the >> modules... >> >> As for python 3.x, It cant even start unless it has some external modules >> >> Unless there is some trick I dont know of, youll get this with a >> static linked py3.1 and no modules... >> --- >> Fatal Python error: Py_Initialize: can't initialize sys standard streams >> ImportError: No module named encodings.utf_8 >> --- >> >> Heres some info I wrote about how to bundle python3.1 with blender. >> >> http://wiki.blender.org/index.php/BlenderDev/Blender2.5/PythonAPI_31 >> >> On Tue, Oct 20, 2009 at 9:48 AM, Nathan Osman >> <george_edison55(a)hotmail.com> wrote: >> > Im kind of new to the Python/C api and I had a couple q's about the >> > interpreter. >> > >> > 1. If i statically link the libpython31.a library to my app are there >> > any other files i need to include for the end users? Im using Windows, btw. >> > 2. How do you get the interpreter output from the console when you are >> > running within a gui environment? Can it be redirected? >> > >> > Thanks, >> > George >> > >> > _________________________________________________________________ >> > New! Faster Messenger access on the new MSN homepage >> > http://go.microsoft.com/?linkid=9677406 >> > _______________________________________________ >> > capi-sig mailing list >> > capi-sig(a)python.org >> > http://mail.python.org/mailman/listinfo/capi-sig >> > >> >> >> >> -- >> - Campbell >> _______________________________________________ >> capi-sig mailing list >> capi-sig(a)python.org >> http://mail.python.org/mailman/listinfo/capi-sig > > ________________________________ > New! Hotmail sign-in on the MSN homepage. -- - Campbell

10 years, 8 months

Couple of Questions About Statically Linking the Interpreter

by Nathan Osman

Im kind of new to the Python/C api and I had a couple q's about the interpreter. 1. If i statically link the libpython31.a library to my app are there any other files i need to include for the end users? Im using Windows, btw. 2. How do you get the interpreter output from the console when you are running within a gui environment? Can it be redirected? Thanks, George _________________________________________________________________ New! Faster Messenger access on the new MSN homepage http://go.microsoft.com/?linkid=9677406

10 years, 8 months

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capi-sig October 2009