[lxgr]

> [...] feature called flexible array members (FAM), which allows the last member of a struct to be a variable length array.

Oh, ISO 8583 has these too!

Sometimes they're even combined with the "feature" described in the article where there's a variable number of fixed-length elements, except for the last element, which is a variable-length string (or sometimes the last field type repeated n times). That's always "fun" to work with.

ISO 8583 really is a living museum of all ideas people had about binary encoding in the last half century or so.