pcunshaded VEX function

Iterate over all of the points of a read-write channel which haven’t had any data written to the channel yet.

See also: pcopen, pciterate, pcimport, pcexport

1. int pcunshaded(int handle, string channel_name)

Like pciterate, this function can be used to iterate over points which were found in a pcopen query. The first argument is the handle returned by pcopen.

However, where pciterate iterates over all the points, this function only iterates over points where the channel in channel_name has not yet been written to.

The function returns 1 while there are points left in the iteration loop, or 0 when there are no further points. This lets you use the function as the condition in a while loop.

Warnings:

• This function will not work correctly when used in multi-threaded OPs. It is not possible to nest pcunshaded or pciterate loops for the same handle. That is, for a single pcopen call, only one pcunshaded or pciterate loop may be entered.

• Computations involving derivatives inside pcunshaded loops may have slightly different results. If derivatives are required for variables which aren’t set by pcimport it may be better to pre-compute the derivatives before the pcunshaded loop is entered.