Function: MTOPEN Purpose: Opens a specified tape unit at a specified density or a binary file. Category: TAPES File: mtiodev.c Author: K.G. Begeman Use: INTEGER MTOPEN( DEVICE ) Input CHARACTER*(*) MTOPEN A non-negative number indicates that the device/file was successfully opened. This number must be used in successive calls to the MTIO routines. A negative number denotes one of the following errors: -1 system error. -3 tape unit already open. -5 tape unit not present. DEVICE Name of device to be opened. MTOPEN will compare this name with devices listed in gip_loc/mtdevices. If not matched (case insensitive match) it will assume that the name is a directory or a environment variable which contains the name of a directory. If the device name is a question mark (?), optionally followed by a keyword and optionally a message, MTOPEN will prompt the user (with MTDEVICE= or the specified keyword) to enter the tape device. The user can then get a list of all available tape units. This is the preferred way of prompting for a tape device. Warning: Code is System dependent! Updates: Jul 20, 1989, KGB, Document created.