[Development] HEADS UP: Don't use QList, use Q_DECLARE_TYPEINFO

[Ulf Hermann]

Mind that all this talk about QList being bad does *not* hold for primitively movable types of exactly sizeof(void *). For example QByteArray, which only consists of a single d-pointer. For those the disadvantages of QList against QVector don't manifest themselves, but the generated code is smaller. Consider the following simple program:

int main(int, char **)
{
     CONTAINER<QByteArray> horst;
     horst << "baum" << "baum";
     qDebug() << horst;
     return 0;
}

Replace CONTAINER with QVector, and I get a binary of 16kb, on my 64bit linux machine. Replace it with QList and I get 12kb:


ulf at zebra:~/dev$ ls -l build-untitled97-5_6-*
build-untitled97-5_6-Release:
total 68
-rw-r--r-- 1 ulf ulf 14568 Jul 13 13:17 main.o
-rw-r--r-- 1 ulf ulf 35953 Jul 13 13:17 Makefile
-rwxr-xr-x 1 ulf ulf 16016 Jul 13 13:17 untitled97


ulf at zebra:~/dev$ ls -l build-untitled97-5_6-*
build-untitled97-5_6-Release:
total 60
-rw-r--r-- 1 ulf ulf  8824 Jul 13 13:18 main.o
-rw-r--r-- 1 ulf ulf 35953 Jul 13 13:17 Makefile
-rwxr-xr-x 1 ulf ulf 12264 Jul 13 13:18 untitled97


-- 
Ulf Hermann, Software Engineer | The Qt Company

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