gcc error constructor is private Walbridge Ohio

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gcc error constructor is private Walbridge, Ohio

How do we avoid this? When your code returns a local variable by value, your compiler might optimize away the local variable completely - zero space-cost and zero time-cost - the local variable never actually exists As if that wasn't bad enough, there's another source of inefficiency when using assignment in a constructor: the member object will get fully constructed by its default constructor, and this might, Why do train companies require two hours to deliver your ticket to the machine?

Here is something that never works: the {body} of a constructor (or a function called from the constructor) cannot get down to a derived class by calling a virtual member function They turn a pile of arbitrary bits into a living object. They do this the same way as described earlier: the return-by-value in function rbv() is implemented as pass-by-pointer, where the pointer points to the location where the returned object is to That's often exactly what you want (and essential for C compatibility), but consider: class Handle { private: string name; X* p; public: Handle(string n) :name(n), p(0) { /* acquire X called

Description Liviu 2004-05-03 02:32:18 UTC When declaring a friend function to a templetized class, function does not have access to private methods: test.h ================== template class foo; template

Conclusion: All other things being equal, your code will run faster if you use initialization lists rather than assignment. Some people feel you should not use the this pointer in a constructor because the object is not fully formed yet. That is often innocuous, since the operating system will typically clean up a process's memory when the process terminates. But all(?) commercial-grade C++ compilers won't do that: the return statement will directly construct x itself.

A technique that provides more intuitive and/or safer construction operations for users of your class. TODO: WRITE THIS UP TODO: WRITE UP TRADEOFFS -- now that you know how to use the Nifty Counter Idiom, be sure you understand both when and (especially!) when not to Bug15254 - friend function does not have access to private method in templeted classes Summary: friend function does not have access to private method in templeted classes Status: RESOLVED DUPLICATE of Watch this space for discussion of Non Static Data Member Initialization in C++11 // Here is the taste of standard C++ NSDMI struct Point { int X = 0; // Look

Previous versions of G++ used to be less strict about this and allowed friend declarations for private class members, for example. If you ever take the address of Fred::maximum, such as passing it by reference or explicitly saying &Fred::maximum, the compiler will make sure it has a unique address. private: void init(char x, int y); }; Foo::Foo(char x) { init(x, int(x) + 7); // ... } Foo::Foo(char x, int y) { init(x, y); // ... } void Foo::init(char x, int How should initializers be ordered in a constructor's initialization list?

I would be really glad if someone could provide me with a solution to this, short of declaring the copy-constructor public. Because of this guideline, the constructor that follows uses s.len_ + 1u rather than len_ + 1u, even though they are otherwise equivalent. c++ xcode3.2 share|improve this question asked Sep 14 '11 at 17:15 RandomUser 1112 Yes, you're allowed to make constructors private. Putting pin(s) back into chain True or False?

Bug3471 - gcc 3.01 reports error about a private copy constructor that shouldn't get called. Hot Network Questions What do I do when two squares are equally valid? Karger's Algorithm question How much interest should I pay on a loan from a friend? Yes, though with some important caveats.

Maybe that's just a bug in gcc 4.1? The solution, as before, is the Construct On First Use Idiom: #include int f(); // forward declaration int g(); // forward declaration int& x() { static int ans = f(); Developing web applications for long lifespan (20+ years) Why doesn't ${@:-1} return the last element of [email protected]? For details, see here.

Description Max de Bayser 2012-06-20 18:47:44 UTC Created attachment 27666 [details] Test case with a class with a private copy constructor Given a class Foo with a private copy constructor, std::is_constructible

Section 12.1 says "A program is ill-formed if the default constructor for an object is implicitly used and the constructor is not accessible." If you replace the derived class constructor MyClass2() For example, if there are 3 static objects, say a, b and c, that use ans during their destructors, the only way to avoid a static deinitialization disaster is if ans Harumph. (That was mostly tongue in cheek. Will rbv() create a temporary Foo object that gets copy-constructed into x?

If that's the case, you should use the explicit keyword: class Foo { public: explicit Foo(int x); explicit operator int(); }; class Bar { public: explicit Bar(double x); explicit operator double(); Before going through the caveats, here is a simple example that is allowed: // Fred.h class Fred { public: static const int maximum = 42; // ... }; And, as with If that's you, please fire yourself before you do any more damage. Many questions relate to very real problems encountered by programmers at work that have very specific / narrow contexts. –Shane MacLaughlin Sep 14 '11 at 17:34 @Shane: Unusual?

See the ISO C++ Standard Committee's defect report #209 for details." And also (http://gcc.gnu.org/bugs.html#cxx_rvalbind): "Starting with GCC 3.4.0, binding an rvalue to a const reference requires an accessible copy constructor. In this case the expression whatever causes a separate, temporary object to be created, and this temporary object is passed into the x_ object's assignment operator. Does the local exist as a separate object, or does it get optimized away? There's ansolutely no way it can suddenly strat requiring a copy constructor for the code which didn't require one under the "canonical" (non-optimized) interpretation. –AnT Oct 13 '09 at 17:19 |

If the constructors of a, b and c use ans, you should normally be okay since the runtime system will, during static deinitialization, destruct ans after the last of those three All this work could be for naught if the whatever expression and/or assignment operator causes the object to close that file and/or release that memory (e.g., if the default constructor didn't Is there a Korean word for 'Syllable Block'? How can I handle a constructor that fails?

Comment 5 Mark Mitchell 2001-11-29 20:19:41 UTC From: mmitchel@gcc.gnu.org To: ericp@mit.edu, gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org, gdr@gcc.gnu.org Cc: Subject: Re: c++/3471: gcc 3.01 reports error about a private copy constructor that shouldn't get By changing the declaration from static Fred* ans = new Fred(); to static Fred ans;, we still correctly handle the initialization situation but we no longer handle the deinitialization situation. Such as: Why does the compiler copy my objects when I don't want it to? So this looks like a bogus constructor namespace check (since the copy constructor shouldn't and doesn't get called in the end anyways).

Browse other questions tagged c++ xcode3.2 or ask your own question. Then that temporary object is destructed at the ;.