NVAPI, CUDA: How can I get current frequency of NVidia Geforce graphic card?

[KShekofteh]

I am using a Geforce GT 740M graphic card on my laptop and a Geforce GTX 760.
I am to write a program with CUDA and NVAPI library in order to read the current frequency of the GPU and then changing it via code.
I could not find a suitable solution in using NVAPI.
Anyone can help me?

Thanks