float agentcliplength(<geometry>geometry, int prim, string clipname)
prim is out of range or is not an agent primitive, or if
clipname is not one of the agent’s animation clips.
The name of the geometry file to reference. Inside Houdini, this may be
op:full_path_to_sop to reference a SOP.
The number of the input to reference. The first input is number
0, the second is
The primitive number.
The name of the animation clip.