TAPRD Procedure (OpenVMS)

Reads the next record on the selected tape unit into the specified array.

TAPRD, array, unit [, byte_reverse]

array A named variable into which the data should be read. The length of array and the records on the tape may range from 14 to 65,235 bytes.

• If array is larger than the tape record, the last portion of array is not changed.

• If array is shorter than the tape record, a data overrun error occurs.

unit A number between 0 and 9 specifying the magnetic tape unit to rewind. (Do not confuse this parameter with file logical unit numbers.)

byte_reverse (optional) If present, causes the even and odd numbered bytes to be swapped after reading, regardless of the type of data or variables. This facilitates reading tapes written on IBM machines.

None.

No data or format conversion, with the exception of optional byte reversal, is performed by TAPRD. The input array must be defined with the desired type and dimensions.

If the read is successful, the system variable !Err is set to the number of bytes read.

SKIPF, TAPWRT

For more information, see Accessing Magnetic Tape in Chapter 8 of the PV-WAVE Programmer's Guide.