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creating a new local variable after a goto

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  creating a new local variable after a goto Lynn McGuire <lynnmcguire5@gmail.com> - 2022-10-12 21:47 -0500
    Re: creating a new local variable after a goto Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-13 03:59 +0100
      Re: creating a new local variable after a goto Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-10-12 20:04 -0700
        Re: creating a new local variable after a goto Ben Bacarisse <ben.usenet@bsb.me.uk> - 2022-10-13 12:23 +0100
      Re: creating a new local variable after a goto Lynn McGuire <lynnmcguire5@gmail.com> - 2022-10-13 21:56 -0500
        Re: creating a new local variable after a goto "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-13 20:11 -0700
          Re: creating a new local variable after a goto Lynn McGuire <lynnmcguire5@gmail.com> - 2022-10-13 22:45 -0500
            Re: creating a new local variable after a goto "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-13 20:54 -0700
              Re: creating a new local variable after a goto "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-13 20:55 -0700
              Re: creating a new local variable after a goto Gawr Gura <gawrgura@mail.hololive.com> - 2022-10-14 04:41 +0000
              Re: creating a new local variable after a goto Ralf Fassel <ralfixx@gmx.de> - 2022-10-14 11:53 +0200
              Re: creating a new local variable after a goto scott@slp53.sl.home (Scott Lurndal) - 2022-10-14 13:48 +0000
                Re: creating a new local variable after a goto Richard Damon <Richard@Damon-Family.org> - 2022-10-14 13:38 -0400
                  Re: creating a new local variable after a goto scott@slp53.sl.home (Scott Lurndal) - 2022-10-14 17:53 +0000
                  Re: creating a new local variable after a goto Tim Rentsch <tr.17687@z991.linuxsc.com> - 2022-11-15 16:26 -0800
                    Re: creating a new local variable after a goto Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-11-15 17:05 -0800
            Re: creating a new local variable after a goto Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-10-14 01:07 -0700
              Re: creating a new local variable after a goto "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2022-10-14 14:32 -0700
            Re: creating a new local variable after a goto Manfred <noname@add.invalid> - 2022-10-15 01:56 +0200
    Re: creating a new local variable after a goto Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-10-12 19:59 -0700
      Re: creating a new local variable after a goto Lynn McGuire <lynnmcguire5@gmail.com> - 2022-10-13 21:55 -0500

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#86939

On 10/12/2022 9:59 PM, Andrey Tarasevich wrote:
> On 10/12/2022 7:47 PM, Lynn McGuire wrote:
>> So, I created a new local variable after a goto:
>>
>>      if (crashed)
>>          goto L99999;
>>
>>      std::string msg;
>>
>> Visual C++ 2015 then informed me that "initialization of 'msg' is 
>> skipped by 'goto L99999'".
>>
>> Is this a real thing, no variable with a constructor can be created 
>> after a goto ?
>>
> 
> Firstly, it is not about its being "after a goto". It is about jumping 
> into the scope of the variable bypassing its initialization. So, it 
> mostly depends on where 'L99999' is located, not on where 'goto' is 
> located.
> 
> You can reproduce the same error "before goto":
> 
>    {
>        std::string msg;
>        skip:;
>    }
> 
>    goto skip;
> 
> Secondly, yes, it is a real thing for variables with automatic storage 
> duration. There's no such restriction for variables with static storage 
> duration though. So, you can actually bypass its construction
> 
>      goto skip;
>      static std::string msg;
>    skip:;
> 
> At 'skip' you will see non-constructed (and therefore unusable) 'msg'.

Thanks !

Lynn

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