You should update the Csound.hlp in the latest version then.

Variable Spectrum Oscillators (Sine - Pulse Train).

ar buzz xamp, xcps, knh, ifn[, iphs]
ar gbuzz xamp, xcps, knh, klh, kr, ifn[, iphs]
ar poscil kamp, kcps, kfrac[, iphs]

Output is a set of harmonically related cosine partials, or a variable
width pulse train. (poscil was introduced in Csound 3.47)

jpff@maths.bath.ac.uk wrote:

> That is because there is no poscil opcode in Csound!  There was a
> suggestion at one time, but it was not released.
> ==John