python和C++调用动态库

python和C++相互调用动态库的方法有4种：

• python调用C/C++编译的动态库
• python调用python编译的动态库
• C/C++调用python编译的动态库
• C/C++调用C/C++编译的动态库

python调用C/C++编译的动态库

mean.c

#include "mean.h"

double mean(double a, double b) {
  return (a+b)/2;
}

mean.h

// Returns the mean of passed parameters
double mean(double, double);

C/C++代码编译

gcc -shared -o libmean.so.1 mean.c

python调用

import ctypes
libmean = ctypes.CDLL("libmean.so.1") # loads the shared library
libmean.mean.restype = ctypes.c_double # define mean function return type

# 方法一
libmean.mean(ctypes.c_double(10), ctypes.c_double(3)) # call mean function needs cast arg types
# 6.5

# 方法二(推荐)
libmean.mean.argtypes = [ctypes.c_double, ctypes.c_double] # define arguments types
libmean.mean(10, 3) # call mean function does not need cast arg types
# 6.5

type(libmean.mean(10, 5)) # returned value is converted to python types
# <type 'float'>

类型映射表

python调用python编译的动态库

python编译出动态库方法，setup.py方法
val.py

import os

def i_sum(a, b):
    # 计算两数之和
    c = a + b
    return c

setup.py

# pip install cpython
from distutils.core import setup
from Cython.Build import cythonize

# 如果有多个python文件在列表中添加
setup(ext_modules=cythonize(["val.py"]))

python编译
在setup.py同级路径，会生成val.cpython-38-x86_64-linux-gnu.so

python调用python编译生成的动态库一定不能改动态库名字

python setup.py build_ext --inplace

python调用

import val

a = 10
b = 2
print(val.i_sum(a,b))
# 12

C/C++调用动态库那就简单了