How to apply the Python main thread

The main Python thread is a conversion method that we often use. But how can we better use this programming language? Next, let's take a look at this article in detail. In the main Python thread or child thread, the following processing is used to call Python functions.

 
 

  
  
{
  
  
Class PyThreadStateLock PyThreadLock;
  
  
// Call python API function processing
  
  
......
  
  
}
 
 

Haha, it's very easy to see.

There are also two macros related to the global lock, Py_BEGIN_ALLOW_THREADS and Py_END_ALLOW_THREADS. These two macros are used to temporarily release the global lock before calling the C function for a long time, and then obtain the global lock again to avoid blocking other python threads to continue running. These two macros can be called in this way.

 
 

  
  
{
  
  
Class PyThreadStateLock PyThreadLock;
  
  
// Call python API function processing
  
  
......
  
  
Py_BEGIN_ALLOW_THREADS
  
  
// Call the C function that requires a long time
  
  
......
  
  
Py_END_ALLOW_THREADS
  
  
// Call python API function processing
  
  
......
  
  
}
 
 

Possible Errors and Solutions

A. a link problem occurs in debug mode in vs 200x.

 
 

  
  
extmodule.obj : error LNK2019: unresolved external 
symbol __imp___Py_Dealloc referenced in function _
PySwigObject_format  
  
  
extmodule.obj : error LNK2019: unresolved external 
symbol __imp___Py_NegativeRefcount referenced in function
 _PySwigObject_format  
  
  
extmodule.obj : error LNK2001: unresolved external symbol
 __imp___Py_RefTotal  
  
  
extmodule.obj : error LNK2019: unresolved external symbol
 __imp___PyObject_DebugFree referenced in function 
_PySwigObject_dealloc  
  
  
extmodule.obj : error LNK2019: unresolved external symbol __imp
___PyObject_DebugMalloc referenced in function _PySwigObject_New  
  
  
extmodule.obj : error LNK2019: unresolved external symbol __imp
__Py_InitModule4TraceRefs referenced in function _init_extmodule 
 
 

It is mainly caused by Py_DEBUG/Py_TRACE_REFS. Modify the pyconfig. h and object. h files under Python \ include. The above is a description of the main Python thread.