QDir::entryList doesn't assign twice

[Kaijun]

I tried to get file list by QDir::entryList, but I found QDir::entryList returns empty list at the second time. Here is example,

QDir dir1("aaa");
QDir dir2("bbb");

QStringList files;

if (!dir1.exists())
return;

files1 = dir1.entryList(QDir::Files | QDir::Readable | QDir::NoDotAndDotDot);
.
.
.

if (!dir2.exists())
return;

QStringList files2;
files2 = dir2.entryList(QDir::Files | QDir::Readable | QDir::NoDotAndDotDot);

In this case files1 is O.K. but files2 is empty. If I use following way, it works.

files2 << dir2.entryList(QDir::Files | QDir::Readable | QDir::NoDotAndDotDot);

I just wonder why the second assign doesn't work.