Wrong usage of QList::ConstIterator & QList::begin() ?
Thiago Macieira
thiago at kde.org
Sat Oct 18 12:24:37 BST 2008
Albert Astals Cid wrote:
>A Dissabte 18 Octubre 2008, Christian Ehrlicher va escriure:
>> Hi,
>>
>> While trying to fix some bugs in KFile* on windows I saw some places
>> like this:
>>
>> for ( QStringList::ConstIterator it = m_dirList.begin();
>> it != m_dirList.end() && !terminationRequested();
>> ++it )
>>
>> Imo the programmer here expects that m_dirList.detach() isn't called
>> but this is wrong.
>>
>> m_dirList.begin() does a detach, returns a non-const iterator and then
>> the iterator is converted to a const iterator (see qlist.h:214 & 238).
>>
>> Therefore I suggest to add QT_STRICT_ITERATORS to the kdelibs flags.
>> Or does this maybe break BC?
>
>This is not wrong, just not what the developer "really wanted" but it
> works just fine, albeit a bit slower.
In this case.
In some cases, mixing const and non-const iterators can lead to crashes,
due to the container detaching in-between and pointers moving around.
QT_STRICT_ITERATORS is good for development, but not for release code.
--
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
PGP/GPG: 0x6EF45358; fingerprint:
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