cufft padding question

does cufftExecC2C auto pad zero if I set the cufftPlanMany size to none power of 2? or it just grab some extra data from rest mem to pad to power of 2.
eg. if I create 900 size in cufftPlanMany, the cufftExecC2C will pad 124 0 into 1024 size or it will grab 124 extra data in ram after 900 samples.

It doesn’t do any padding.

An FFT can be conducted on a non-power-of-2 size.

Is it because cufft create plans for different fft size at compile time? Just like FFTW?