www.neuron.yale.edu

I found that if one uses the third form of Vector's record function (the one with the separate time vector) I get no recorded data for either vector.

Here's a sample code that reproduces the bug for me:
On my computer, it prints out 0's for both of the vectors' sizes. If I do it this way, however, everything works as expected:
I am using a slightly modified NEURON 6.1 on Windows, but my changes to it have not touched any of the low-level implementations so I do not think I broke it myself. I don't have access to a vanilla install of NEURON right now, but I shall test to see if this is reproducible there as well as soon as I am able.

Not a NEURON bug. In the form vdest.record(&var, tvec), tvec is a Vector whose elements specify the times at which var will be captured to vdest. Quoting from the documentation of Vector record http://www.neuron.yale.edu/neuron/stati ... tml#record

At the end of fadvance, var will be saved if t (after being incremented by fadvance) is equal or greater than the associated time of the next index.
. . .
The record semantics can be thought of as:
var(t) -> v.x[index]

The default relationship between index and t is t = index*dt.
In the second form, t = index*Dt.
In the third form, t = tvec.x[index].

If tvec is empty, or its elements are > t at the end of the simulation, no values will be captured to vdest. In your code example that fails to record anything, tvec is empty.

Ah, I see. I misunderstood what the manual was implying. Thanks for the clarification.

I have made similar misinterpretations myself. Much of the documentation is concise "to a fault." Even when meanings seem evident, it is always a good idea to test before using.