How Python refers to DLL files

The examples in this article describe how Python references dll files. Share to everyone for your reference. The specific analysis is as follows:

The interface in calling DLL files in Python is relatively straightforward, as we have a Test.dll file, internally defined as follows:

extern "C" {int __stdcall Test (void* p, int len) {  return len;}}

In Python we can load the following two different ways

1.

Import Ctypesdll = ctypes.windll.LoadLibrary (' Test.dll ')

2.

Import Ctypesdll = cTYPES. Windll (' Test.dll ')

Where Ctypes.windll is an object of the Ctypes.windll class, it is already defined in the cTYPES module. There is a test interface in the Test.dll, which can be called directly with the DLL.

NRst = Dll.test () print nRst

Since two parameters are passed in the test interface, one is a pointer of type void, which points to a buffer. One is the length of the buffer. So we're going to get pointers and lengths to the strings in Python.

#方法一: sbuf = ' aaaaaaaaaabbbbbbbbbbbbbb ' pStr = ctypes.c_char_p () pstr.value = Sbufpvoid = Ctypes.cast (PStr, ctypes.c_void_ p). Valuenrst = Dll.test (pVoid, Len (pstr.value))

#方法二: test = Dll.testtest.argtypes = [Ctypes.c_char_p, ctypes.c_int]test.restypes = Ctypes.c_intnrst = Test (sbuf, Len ( SBUF))

If you modify the interface in Test.dll, the definition is as follows:

extern "C" {   int __cdecl test (void* p, int len)  {     return len;   }}

Because the interface defines a call in the cdecl format, it is also necessary to use the appropriate type in Python

1.

Import Ctypesdll = ctypes.cdll.LoadLibrary (' Test.dll ') # #注: Generally under Linux for TEST.O files, you can also use the following methods: # #dll = Ctypes.cdll.LoadLibrary (' TEST.O ')

2.

Import Ctypesdll = cTYPES. Cdll (' Test.dll ')

Hopefully this article will help you with Python programming.

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