Threading
Hello, I'm trying to call Python routines from C/C++. These routines must intereact in a multi-thread environment. I mean that routine A will loop waiting for a condition of routine B. This condition are coded in C so I don't need routine A running in the same interpreter of routine B. I tried using: PyEval_AcquireLock(); PyInterpreterState* mainInterpreterState = mainThreadState->interp; PyThreadState * myThreadState = PyThreadState_New(mainInterpreterState); PyThreadState_Swap(myThreadState); ... Call Python code here PyThreadState_Swap(NULL); PyEval_ReleaseLock(); Obviosly, I called thread initialization code in the main thread like http://www.linuxjournal.com/article/3641 The problem with this code is that I hold the interpreter lock when calling routine A or B so they cannot run simultaneous and that is a requierement for me (as I explained before). It executes some code of the routine I called but then it hungs. If I release the lock before calling the Python code it doesn´t work neither somhow. Then I tried to create an interpreter for each thread. It is not desirable but it's acceptable: PyEval_AcquireLock(); PyThreadState* myThreadState = Py_NewInterpreter(); PyThreadState_Swap(myThreadState); PyEval_ReleaseLock(); ... Call Python code here PyEval_AcquireLock(); PyThreadState_Swap(NULL); Py_EndInterpreter(myThreadState); PyEval_ReleaseLock(); But it doesn't work. It seems that it requieres to take the lock to call Python code. If I comment the PyEval_ReleaseLock line and PyEval_AcquireLock pair it calls other threads before hunging. I saw some threads talking about some similar situations and I saw no answer to this. This issue remains unsolved? Thanks on advance, Pablo -- http://www.nektra.com -- http://mail.python.org/mailman/listinfo/python-list
C++ Binding with Threads
Hello, I want to embed Python in an application and use an API of the application from Python. The application uses a library that creates several threads and I the users of the application will write Python scripts handling this events. The problem is that I having problems with threads. I saw that I have to PyEval_InitThreads and then PyThreadState_New and PyThreadState_Swap from the new thread but this way to solve the problem doesn't work for me because I need to let 2 or more threads run at the SAME time. The interpreter lock doesn't let them run at the same time so I'm looking for another solution. I saw Py_NewInterpreter and I tried to use it but it doesn't work if I don't keep the lock. Can anyone help me to solve this issue or tell me 'Forget it!'? Thanks on advance, Pablo Yabo -- http://mail.python.org/mailman/listinfo/python-list
C++ Binding with Threads
Hello, I want to embed Python in an application and use an API of the application from Python. The application uses a library that creates several threads and I the users of the application will write Python scripts handling this events. The problem is that I having problems with threads. I saw that I have to PyEval_InitThreads and then PyThreadState_New and PyThreadState_Swap from the new thread but this way to solve the problem doesn't work for me because I need to let 2 or more threads run at the SAME time. The interpreter lock doesn't let them run at the same time so I'm looking for another solution. I saw Py_NewInterpreter and I tried to use it but it doesn't work if I don't keep the lock. Can anyone help me to solve this issue or tell me 'Forget it!'? Thanks on advance, Pablo Yabo -- http://www.nektra.com -- http://mail.python.org/mailman/listinfo/python-list
Re: C++ Binding with Threads
I've found a workaround for me project that I'll share.
The solution is to release the interpreter lock when a function of my wapper
is called, I mean from Python a function of C++ is called so I released the
interpreter lock and take it before returning to Python.
It's important to provide Sleep functions in your C++ code. Otherwise,
multi-threading will not work at all. If most of the work is done in your
C++ code, using this workaround will solve the issue.
To make it easier I've wrote a class to create an instance at the beginning
of each wrapped function.
Here is the constructor / destructor:
PythonAutoLock::PythonAutoLock()
{
PythonMgr *mgr = PythonMgr::instance();
_state = PyThreadState_Get();
PyThreadState_Swap(NULL);
PyEval_ReleaseLock();
}
PythonAutoLock::~PythonAutoLock()
{
PythonMgr *mgr = PythonMgr::instance();
PyEval_AcquireLock();
PyThreadState_Swap(_state);
}
Pablo Yabo
--
http://www.nektra.com
On 8/13/07, Pablo Yabo <[EMAIL PROTECTED]> wrote:
>
> Hello,
>
> I want to embed Python in an application and use an API of the application
> from Python.
> The application uses a library that creates several threads and I the
> users of the application will write Python scripts handling this events.
>
> The problem is that I having problems with threads. I saw that I have to
> PyEval_InitThreads and then PyThreadState_New and PyThreadState_Swap from
> the new thread but this way to solve the problem doesn't work for me because
> I need to let 2 or more threads run at the SAME time.
> The interpreter lock doesn't let them run at the same time so I'm looking
> for another solution. I saw Py_NewInterpreter and I tried to use it but it
> doesn't work if I don't keep the lock.
>
> Can anyone help me to solve this issue or tell me 'Forget it!'?
>
>
> Thanks on advance,
> Pablo Yabo
> --
> http://www.nektra.com
>
--
http://mail.python.org/mailman/listinfo/python-list
Thread structures BUG?
Hello, I create lots of threads that run a script and I have a problem when a thread is created with the same threadId that existed before. When a new thread is started I use this code to enter the interpreter: // create a thread state object for this thread PyEval_AcquireLock(); threadState = PyThreadState_New(mainInterpreterState); PyThreadState_Swap(threadState); and when the thread finishes: PyThreadState_Swap(NULL); PyThreadState_Clear(info); // delete my thread state object PyThreadState_Delete(info); PyEval_ReleaseLock(); Everything works smoothly until a thread id is re-used. I've been testing what is happening and the problem is that PyGILState_GetThisThreadState() returns a PyThreadState for the reused thread id. I changed my code to call PyGILState_GetThisThreadState() before creating the PyThreadState. But if I try to use the returned PyThreadState (that shouldn't exist because I've already deleted) I got an error when trying to access the interpreter dictionary. The workaround that I found is to keep all PyThreadState structures without calling PyThreadState_Clear / PyThreadState_Delete. When a new thread is created I call PyGILState_GetThisThreadState(). If it returns something I reuse the structure. In this way, my code works. Thanks, Pablo Yabo -- http://www.nektra.com -- http://mail.python.org/mailman/listinfo/python-list
