The readt statement reads a tape record and assigns the value returned to a specified variable.
Syntax
readt var [then|else|onerr statement.block] |
Description
The length of the tape record is specified by the most recently executed TCL t-att command.
The then clause is taken if the operation is successful.
Either else or onerr can be specified, but not both. If the tape unit has not been attached or if an end-of-file (eof) mark is read, the else or onerr clause, if present, is executed. In addition, the onerr clause can be used to check for end-of-tape (eot), tape unit not ready, parity error, or block transfer error.
NOTE |
If a readt is attempted without a device attached, FlashBASIC or BASIC takes the else clause with system(0) = 1, but FlashBASIC or BASIC attempts the read. |
Example(s)
The example below reads a series of tape records and displays the first 25 bytes of each record. The readt else clause is usually taken when an end-of-tape or end-of-data condition is reached. The system(0) function indicates whether there are any other unexpected problems.
execute ’t-att’ rewind else stop eot=0 loop readt rec else eot=1 until eot do print trim(rec[1,25]) repeat |
See Also
onerr Clause, readtx Statement, rewind Statement, set-sct Command, Statement Blocks, Statements and Functions, system() Function, t-att Command, t-select Command, t-stat Command, then Clause, then/else Statement Blocks, weof Statement, writet Statement