using ippsDFTInit_C with using ippsFFTInit

Hello.

it is confusing the difference between DFTInit and FFTInit

for example:

{

    int *sizeSpec, *sizeInit, *sizeBuff;

    IppDFTSpec_C_64fc *pSpecDfr, *pSpecFft;

    Ipp8u *pSpecFft, *pInit, *pBuff;

#ifdef USE_DFT

    ippsDFTGetSize_C_64fc(16, IPP_FFT_NODIV_BY_ANY, ippAlgHintNone, &sizeSpec, &sizeInit, &sizeBuff);

#else

    ippsFFTGetSize_C_64fc(4, IPP_FFT_NODIV_BY_ANY, ippAlgHintNone, &sizeSpec, &sizeInit, &sizeBuff);

#endif

    pSpec = ippsMalloc_8u(sizeSpec); pInit = ippsMalloc_8u(sizeInit); pBuff = ippsMalloc_8u(sizeBuff);

#ifdef USE_DFT

    ippsDFTInit_C_64fc(10, IPP_FFT_NODIV_BY_ANY, ippAlgHintNone, pSpec , pInit );

#else

    ippsFFTInit_C_64fc(&pSpecFft, 4, IPP_FFT_NODIV_BY_ANY, ippAlgHintNone, pSpec, pInit ); // here we provide additional argument

#endif

    // using fft or dft converting functions

}

Did I making right the initialization for FFt and DFT?

Why the interface is different for DFT and FFT? I mean why for FFT I need to provide additional argument for Init function? Why it can be done in the same way for DFT and FFT? It is confusing.