Ctypes捕获异常 [英] Ctypes catching exception

问题描述

我在玩ctypes和C / C ++ DLLs
我有一个非常简单的数学dll

  double Divide（double a，double b）
 {
 if（b == 0）
 {
 throw new invalid_argument（b can not be zero！ ; 
} 
 
返回a / b; 
} 
  

它工作到目前为止
唯一的问题，我得到一个WindowsError Python中的异常和我无法检索文本
b不能为零
是否有一些特殊的异常类型必须抛出？还是必须修改Python代码？
python代码：

 来自ctypes import * 
 
 mathdll = cdll.MathFuncsDll 
 divide = mathdll.Divide 
 divide.restype = c_double 
 divide.argtypes = [c_double，c_double] 
 
 try：
 print divide（10,0） 
除了WindowsError：
 printlalal
 except：
 printdada
  

$ b b

解决方案

首先，你不应该在C ++中使用异常规范。这是C ++的一个可怕的特性，它已在最新标准中被弃用。另外，语法 throw（...）根本不是有效的C ++，这行不使用像gcc这样的标准编译器编译：

  double Divide（double a，double b）throw（...）
  

我认为你依赖于一个非标准的Visual C ++扩展，据我所知，这是无用的，因为Visual C ++忽略所有的异常规范，除非 throw（）没有参数。

通过Python 2.7.3的ctypes文档我看不到任何引用C ++和通过ctypes调用的C ++代码抛出异常。看起来ctypes仅用于调用C函数，不处理C ++异常。

I'm playing a little bit with ctypes and C/C++ DLLs I have a quite simple "math" dll

double Divide(double a, double b)
{
    if (b == 0)
    {
       throw new invalid_argument("b cannot be zero!");
    }

    return a / b;
}

It works so far the only problem, i get a WindowsError Exception in Python and I cannot retrieve the text b cannot be zero Is there some special exception type I must throw? Or must the Python code be altered? python code:

from ctypes import *

mathdll=cdll.MathFuncsDll
divide = mathdll.Divide
divide.restype = c_double
divide.argtypes = [c_double, c_double]

try:
    print divide (10,0)
except WindowsError:
    print "lalal"
except:
    print "dada"

解决方案

First of all you should not use exception specifications in C++. This is a horrible feature of C++ and it has been deprecated in the latest standard. Also, the syntax throw(...) is not valid C++ at all, this line does not compile with a standard conforming compiler like gcc:

double Divide(double a, double b) throw (...)

I think you are relying on a non-standard Visual C++ "extension", which is, as far as I know, useless anyway, cause Visual C++ ignores all exception specifications unless throw() has no arguments.

Going through the ctypes documentation for Python 2.7.3 I can't see any reference to C++ and throwing exceptions from C++ code called via ctypes. It seems ctypes was meant for calling C functions only and does not handle C++ exceptions.

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