basic.readt
Reads one tape record.
Syntax
readt variable [then | else | onerr statement.block]
Description
reads a tape record and assigns the value returned to a specified variable.
The length of the tape record is specified by the most recently executed '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' statement can be used to check for end-of-tape (EOT), tape unit not ready, parity error, or block transfer error. See the system(0) function.
See the 'then/else construct' for an explanation on the use of 'then' and 'else' clauses in statements that allow or require them.
Example
execute 't-att'
rewind else stop
eot=0
loop
readt rec else eot=1
until eot do
print trim(rec[1,25])
repeat
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.
See Also
User Comments
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