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digitalmars.D.bugs - [Issue 12252] New: struct default constructors that execute code.

reply d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12252

           Summary: struct default constructors that execute code.
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: remotion4d gmail.com


--- Comment #0 from Remo <remotion4d gmail.com> 2014-02-25 06:56:36 PST ---
extern(C)  int w_init(CWrapper *p);
extern(C) void w_free(CWrapper *p);

struct CWrapper {
    this() { //not possible
       w_init(&this);
    }
    ~this() {
       w_free(&this);
    }
}

void main(){
    S s; //should call w_init()
    S s1 = S(); //should call w_init() too
}


While porting C++ code to D2 it is some times necessary to do be able to mimic
C++ class/struct behavior. 

Using  this(int dummy){ ... } as a workaround compiles but does not work.
Other workarounds are complicated and error phone.

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Feb 25 2014
next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12252


bearophile_hugs eml.cc changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bearophile_hugs eml.cc
           Severity|normal                      |enhancement


--- Comment #1 from bearophile_hugs eml.cc 2014-02-25 07:03:23 PST ---
Converted to enhancement, because D is working as designed here (and from past
discussions I have seen, this is at best a controversial change).

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prev sibling next sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12252


yebblies <yebblies gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |yebblies gmail.com
         Resolution|                            |DUPLICATE


--- Comment #2 from yebblies <yebblies gmail.com> 2014-02-28 23:51:14 EST ---
*** This issue has been marked as a duplicate of issue 3852 ***

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Feb 28 2014
prev sibling parent d-bugmail puremagic.com writes:
https://d.puremagic.com/issues/show_bug.cgi?id=12252



--- Comment #3 from Remo <remotion4d gmail.com> 2014-02-28 05:07:29 PST ---
Ok then why any other workarounds for this problem do not work too ?

Here is one possible workaround that does not work.
struct S
{
     disable this();
     disable this(this);

    this(int i){ }
    static S opCall(){
        S s = S(123);
        return s;
    }
}

This would help to find places in ported C++ code that need to be changed but
it does not compiles.

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