[fitsbits] question about cfitsio

[Greg Hennessy]

I am trying to use cfitsio 2.1. I want to create a fits binary table,
add rows to it, and it won't be known in advance how many rows I
have. I thought I might try writing an element at a time via
fits_write_col, but that routine must not be used to write to variable
length array columns. I don't see what routine should be used. I can
see a fits_insert_rows, but it isn't clear to me how to set the data
in the row after I fits_insert_rows the row.

Can anyone offer advice on what I am missing?