[Interest] QList and erase problem...

[Igor Mironchik]

Hi,

it seems that problem not in the iterating and deletion from cantainer...

I wrote simple test app and everything is ok.

But something here crashes my app and only in release mode, so I can't 
understand what is the problem...

And ideas?

9/14/2015 6:06 PM, André Somers пишет:
> Op 14-9-2015 om 16:57 schreef Igor Mironchik:
>> Hi,
>>
>> I ran into this problem...
>>
>> void
>> ImageFilesStoragePrivate::removeAllImages(
>>        QList< ImageRecord > & images,
>>        ImageFilesStorage::ImageType type )
>> {
>>        QList< ImageRecord >::Iterator it = images.begin();
>>        QList< ImageRecord >::Iterator last = images.end();
>>
>>        while( it != last )
>>        {
>>            if( (*it).m_type == type )
>>            {
>>                LOG( DebugLogLevel, "Before real deletion" )
>>                removeFromDatabase( it );
>>                LOG( DebugLogLevel, "After real deletion" )
>>
>> //            it = images.erase( it ); // LOOK AT THIS LINE !!! If I
>> uncomment it and comment next line - crash...
>>                ++it;
>>
>>                LOG( DebugLogLevel, QString( "it == last : %1" ).arg( ( it
>> == last ? "true" : "false" ) ) )
>>            }
>>            else
>>                ++it;
>>        }
>> }
>>
>> What is wrong?
> A lot is wrong.
>
> First, you are not using standard algorithms to do standard things. I'd
> say std::remove_if with std::erase would be a better way to solve the issue.
>
> Then in general, if you delete from the container, iterators are going
> to be invalidated. Iterate backwards if you are going to delete items
> from the container.
>
> Last: you probably don't want to use QList but QVector.
>
> André
>
>
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