🚀 go-pugleaf

On 05 Apr 96 02:58:28 GMT, Alan Griffiths <aGriffiths@ma.ccngroup.com>
wrote:

>I've just tried porting some code to MSVC4 (it compiles and works with 
>SC7.1 and BC4.5).
>
>In effect it appears that the Microsoft compiler _requires_ anything 
>thrown as an exception to have an accessible copy constructor.  (I've 
>tended to make copy constructors private to ensure catch-by-reference
>and aviod slicing bugs.)
>
>Looking through the DWP I can't see any reason to require a copy 
>constructor, but there are references to copying temporaries.
>
>Is MSVC4 correct?
>
>code:
>class MyBaseException {
>public:  MyBaseException() {}
>         virtual char* what() = 0;
>private: MyBaseException(const MyBaseException&);
>};
>
>class MyException1 : public  MyBaseException {
>public:     virtual char* what() { return "MyException1"; }
>};
>
>int main() {
>    try     {
>        throw MyException1();
>// error C2700: 'class MyException1' : cannot be thrown (use -W4 for more info)
>
>// warning C4671: 'MyException1' : the copy constructor is inaccessible
>    } catch (MyBaseException& e) {
>        cout << "OK - got here (" << __LINE__ << ") : have a " << e.what()
>		<< endl;
>    } catch (...) {
>        cout << "ERROR - got here (" << __LINE__ << ")" << endl;
>    }
>    return 0;
>}
>

Here's what BC++ 5.0 generates...

Borland C++ 5.0 for Win32 Copyright (c) 1993, 1996 Borland
International
MS-EXCPT.CPP:
Error MS-EXCPT.CPP 15: Compiler could not generate copy constructor
for class 'MyException1' in function main()
*** 1 errors in Compile ***

It appears we have an agreement in interpretation of the DWP.

Jason
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