Re: C++ constructors called as args

[Michal Liptak <liptak at isdd dot sk>]

could you post the whole code, because this compiles fine:
class A  {
        // forward decl
};

class B {
        public:
        B( const A& a ) {}
        B( const B& b ) {}
};

class C {
        public:
        void F1( A a ) { F2(a); }
        void F2( B b ) {}
};

int main(void) {
        C c;
        A a;
        c.F1(a);
        return 0;
}

plus I don't see why you pass arguments to F1() and F2 by value.. is it intended?

m.

On Sun, 02 Mar 2003 23:56:33 -0800
Michael Hunley <mhunley at pocketpurchase dot com> wrote:

>I will post this to the news groups as well, if this is not the correct 
>place to ask this question my humble apologies.
>
>I am working under RedHat Linux 8.0 which reports I am using GCC 3.2-7 
>(which does not seem to match the GNU gcc versioning, but...).  I have 
>3.2.2, but have not deployed yet.
>
>I am brand new to linux and gcc and am trying to port an app from Windows 
>written in C++ using MSVC 6.
>
>I have some simple class combinations that effectively look like:
>
>class A;        // forward decl
>
>class B {
>         B( const A& a );
>         B( const B& b );
>};
>
>class C {
>         void F1( A a ) { F2(a); }
>         void F2( B b );
>};
>
>I get several errors from the above situation, apparently because g++ does 
>not like calling the constructor to create a temp B from an A.  One of the 
>messages is that it did do it, but the code does not compile.  The only fix 
>I can find is to change F1 to look like:
>         void F1( A a ) { B b(a); F2(b); }
>Which would seem like what the compiler ought to do automatically 
>anyway.  Instead I get a main error that:
>         Cannot find B::B(B)
>
>I have searched the docs and the news groups and can't seem to find any 
>docage on this.  Is there a compile switch I need to get the auto creation 
>of the temp?  Is there another work around besides changing all the code 
>that does that sort of thing to create my own temp explicitly?  BTW: this 
>code compiles fine under MSVC 6 and Kylix 3.
>
>thanks in advance.
>
>Michael Hunley
>Senior Engineer
>PocketPurchase, Inc.  
>