[Interest] QStringBuilder buffer overflow with string litteral?

[Olivier B.]

Oh, you are right, thanks. I thought the + operator was on a QString and
adding a char would be faster than adding a 1-char string, but it just
changed the char* pointer address instead.

Le lun. 25 janv. 2021 à 15:32, Giuseppe D'Angelo via Interest <
interest at qt-project.org> a écrit :

> Hi,
>
> Il 25/01/21 13:56, Olivier B. ha scritto:
> >          fields += (fields.isEmpty() ? "" : ", ") + '"' + field + '"';
>
> QStringBuilder usage is a red herring, pay close attention at what
> you're doing in the first +: you're summing a const char * (result of
> the ternary operator) with a char; that does not do string concatenation...
>
> > Passing one/both of the operands of the ternary operator as QStrings
> makes the problem disappear.
>
> That however kills the advantage of QStringBuilder. Use QStringView /
> QLatin1String instead.
>
> Tip: always define QT_NO_CAST_FROM_ASCII (or the more lenient
> QT_RESTRICTED_CAST_FROM_ASCII) in any Qt project.
>
> HTH,
> --
> Giuseppe D'Angelo | giuseppe.dangelo at kdab.com | Senior Software Engineer
> KDAB (France) S.A.S., a KDAB Group company
> Tel. France +33 (0)4 90 84 08 53, http://www.kdab.com
> KDAB - The Qt, C++ and OpenGL Experts
>
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