Y must be a simple integer scalar or 1 or 2 element vector containing the file tie number followed by an optional passnumber. If the passnumber is omitted it is assumed to be zero. The result is a 4 element numeric vector containing the following:
| Element | Description |
|---|---|
| 1 | the number of first component |
| 2 | 1 + the number of the last component, (i.e. the result of the next ⎕FAPPEND) |
| 3 | the current size of the file in bytes |
| 4 | the file size limit in bytes |
⎕FSIZE 1 1 21 65271 4294967295