[Bug c++/53753] New: stack based constructor is not called for Class1 Object1()

[Bug c++/53753] New: stack based constructor is not called for Class1 Object1()

[kiran.puttur at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53753

             Bug #: 53753
           Summary: stack based constructor is not called for  Class1
                    Object1()
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: kiran.puttur@gmail.com


I have gcc version 4.7.0 (Ubuntu/Linaro 4.7.0-7ubuntu3) I have following
program

#include<iostream>
class Myclass
{
public:
       Myclass() {
        std::cout<<"Value of mInt : "<< mInt << " value mStr : " << mStr
<<std::endl;
        std::cout<<"test complete" << std::endl;
        }
protected:
        int mInt;
        std::string mStr;
};

int main(void)
{
        Myclass instance1();
        return 0;
}

if I compile the program with following options
#g++ -W -Wall -Wextra -pedantic -std=c++0x -c inclass-member-initialize.cpp -o
inclass-member-initialize.o
#g++  inclass-member-initialize.o -o output

and If I run the output program 
#output
It doesn't show constructor initialization statement at all

But if i modify the line as
             Myclass instance1 = Myclass();

Then the constructor is getting called, and I can see test messages.

Even constructor on heap also shows up without any issues such as
             Myclass *instance1 = new Myclass();

works just fine,

Just the intialization like Myclass instance1() is currently having issues

Is this expected ?

[Bug c++/53753] stack based constructor is not called for Class1 Object1()

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53753

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-06-23 08:55:40 UTC ---
>        Myclass instance1();

I think this is really a function declaration name instance1 returning Myclass
and not a variable declaration.

[Bug c++/53753] stack based constructor is not called for Class1 Object1()

[daniel.kruegler at googlemail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53753

Daniel Krügler <daniel.kruegler at googlemail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |daniel.kruegler at
                   |                            |googlemail dot com

--- Comment #2 from Daniel Krügler <daniel.kruegler at googlemail dot com> 2012-06-23 09:58:58 UTC ---
I agree with Andrew, there is no object defined in the code, so the behaviour
is expected. 

Since you are using C++11 mode you can use a pair of braces here:

Myclass instance1{};

This will be a guaranteed variable definition and allows uniform initialization
even for built-in types.

[Bug c++/53753] stack based constructor is not called for Class1 Object1()

[kiran.puttur at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53753

--- Comment #3 from Kiran Puttur <kiran.puttur at gmail dot com> 2012-06-23 10:14:38 UTC ---
Thanks Andrew, Daniel,

If I use the braces {} then I can see my testing strings printed in the program
output

[Bug c++/53753] stack based constructor is not called for Class1 Object1()

[kiran.puttur at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53753

--- Comment #4 from Kiran Puttur <kiran.puttur at gmail dot com> 2012-06-23 10:15:22 UTC ---
Thanks Andrew, Daniel,

If I use the braces {} then I can see my testing strings printed in the program
output

[Bug c++/53753] stack based constructor is not called for Class1 Object1()

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53753

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-06-23 11:57:53 UTC ---
see http://en.wikipedia.org/wiki/Most_vexing_parse