CODEWITHSUNDEEP
c++python-2.7ctypes
Suave Nti
Suave Nti

Reputation: 3739

Python ctypes calling simple c++ dll

I am really having a hard time to call a simple c++ dll from python using ctypes

Below is my C++ code :

#ifdef __cplusplus
extern "C"{
#endif
  __declspec(dllexport) char const* greet()
{
  return "hello, world";
}
#ifdef __cplusplus
}
#endif

...

My Python code :

import ctypes
testlib = ctypes.CDLL("CpLib.dll");
print testlib.greet();

When i run my py script, I get this strange return value of -97902232

Kindly assist.

Upvotes: 2

Views: 3862

Answers (1)

David Heffernan
David Heffernan

Reputation: 612794

You didn't tell ctypes what type the return value is, and so it assumes that it is an integer. But it is in fact a pointer. Set the restype attribute to let ctypes know how to interpret the return value.

import ctypes 
testlib = ctypes.CDLL("CpLib.dll")
testlib.greet.restype = ctypes.c_char_p
print testlib.greet()

Upvotes: 3

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