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	<201410140927.36252.thomas@thomaszander.se>
Date: Tue, 14 Oct 2014 10:04:20 +0200
Message-ID: <CA+s+GJBvOH9cW_yaK7ZEDUYznDe=KeoMYMZ3KF=P503JceWFeg@mail.gmail.com>
From: Wladimir <laanwj@gmail.com>
To: Thomas Zander <thomas@thomaszander.se>
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Cc: Bitcoin Dev <bitcoin-development@lists.sourceforge.net>
Subject: Re: [Bitcoin-development] Malleable booleans
Precedence: list

On Tue, Oct 14, 2014 at 9:27 AM, Thomas Zander <thomas@thomaszander.se> wro=
te:
> On Tuesday 14. October 2014 04.34.16 Pieter Wuille wrote:
>> This means that scripts that use booleans as inputs will be inherently
>> malleable.
>
> I've ran into this issue in C++ often enough,
> a funny example is assigning "2" to a native c++ bool and then you can do=
 a
>  if (myBool =3D=3D true)
>  else if (myBool =3D=3D false)
> and neither of them will hit.

Off topic nit: I think you're confused with custom BOOL typedefs in C?
C++ booleans are protected against this (C++ standard =C2=A74.7/4 according
to Google).:

```
#include <stdio.h>

int main()
{
    bool myBool;
    myBool =3D 2;
    if (myBool =3D=3D true)
        printf("It is true!\n");
    else if (myBool =3D=3D false)
        printf("It is false!\n");
    else
        printf("It is something else!\n");
}
```

Prints 'It is true'. You can also use bool(something) as equivalent of
`x !=3D 0`; as in `assert(bool(2) =3D=3D true);`.

Wladimir