fileptr(lun [, offset] [, /start, /eof, /advance])
fileptr, lun [, offset] [, /start, /eof, /advance]
Show or set a file pointer.
fileptr,lun shows and
fileptr(lun) returns the position of the file pointer of
lun in bytes from the start of the file. If
offset and/or a keyword are specified, then the file
pointer is modified. If a keyword is specified but not
offset, then zero is taken for
can move a file pointer beyond the end of a file, but not before the
beginning of the file. If you read data from beyond the end of a file,
or from a dataless gap in a file, then zeros are returned.
counts from the start of the file.
counts from the end-of-file marker (which is one byte beyond the last byte in the file).
counts from the current position.
If no keyword is defined, then non-negative
from the start and negative
offset from the end-of-file
-1 pointing at the last byte of the file). The
function version returns
1 on success,
0 or failure.
See also: openr, openw, openu