See P2169 A Nice Placeholder With No Name

 

https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2023/p2169r3.pdf

https://github.com/cplusplus/papers/issues/878
 

-----Ursprüngliche Nachricht-----
Von: Frederick Virchanza Gotham via Std-Proposals <std-proposals@lists.isocpp.org>
Gesendet: Sa 10.06.2023 16:27
Betreff: [std-proposals] Dummy names for dummy objects
An: std-proposals <std-proposals@lists.isocpp.org>;
CC: Frederick Virchanza Gotham <cauldwell.thomas@gmail.com>;
Sometimes I have code like this:

void Func(void)
{
   OnScopeExit dummy( [](){ ::close(global_fd); } );

   // Do more stuff here
}

If I later amend this function so that further down there's another
'OnScopeExit', then I have to name the second one "dummy1", and the
third one "dummy2" and so on.

For the sake of making it easier to patch source files, I propose that
we can give an object a dummy name as follows:

void Func(void)
{
   OnScopeExit __dummy( [](){ /* Do Something */ } );

   // Do more stuff here

   OnScopeExit __dummy( [](){ /* Do Something */ } );

   // Do more stuff here

   OnScopeExit __dummy( [](){ /* Do Something */ } );
}

These objects don't have a name clash. If you try to access an object
by the name '__dummy', it accesses the most recently defined dummy
object:

void Func(void)
{
   OnScopeExit __dummy( [](){ /* Do Something */ } );

   // Do more stuff here
   _dummy.SomeMethod();   // refers to the object defined 3 lines above

   OnScopeExit __dummy( [](){ /* Do Something */ } );

   // Do more stuff here
   _dummy.SomeMethod();   // refers to the object defined 3 lines above

   OnScopeExit __dummy( [](){ /* Do Something */ } );
}
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