non-standard for-loop syntax

[freebie]

Can someone explain this for loop syntax:
for(;$position<$length; )

thanks

[laserlight]

equivalent to

while ($position<$length)

[freebie]

thanks.
Is there any situation where this is preferable to using "while" instead.

[laserlight]

None that I can think of.
It should be preferable to use a while loop as that would be clearer.