What does "pad" mean for QColor?

[hxcan]

I'm reading the documentation of "Serializing Qt Data Types".
I found that when serializing a QColor , QDataStream outputs the following things:spec,alpha,red,green,blue,pad.

What does the pad value mean for a QColor? And what does pad mean for a real-life color?

[mvuori]

See: http://qt.gitorious.org/qt/qt/blobs/...nting/qcolor.h

I guess it is just nonsignificant "padding" to get the size of all alternative representations of color have the same number of bytes (see the unions in QColor class).