Output of mlab.specgram compared to MATLABs?

Greetings list,

I am trying to figure out the differences between mlab.specgram and
MATLABs spectrogram functions. I am mostly interested in MATLABs [.., P]
output which is the PSD for each segment. It seems to me that the output
of mlab.specgram's (Pxx, ..) is in fact the equivialent of MATLABSs [.., P] and
not [S, ...], is this correct?

Thanks, Gaute