(Solved)Hiding or Bug?

[vpwal]

Hi all .
First of all look here and find setFrequency() function .
"look here":http://qt-project.org/doc/qt-4.8/qaudioformat.html#public-types
the result no such word/function.
But when i do coding i found setFrequency() function.
Even many of Examples provided by Qt docs uses setFrequency() function.
"given here":http://qt-project.org/doc/qt-4.8/qaudiooutput.html#details
Why ? is it bug on webpage ?.