OPEN_NEW

Syntax

OPEN_NEW #channel, device_filename or

OPEN_NEW #channel, [device_]filename(Toolkit II only) or

OPEN_NEW #channel, device_filename, type (Minerva v1.80+ only)

Location QL ROM, Toolkit II

This command is yet another specialised version of OPEN. This time it is aimed at providing a means of creating a new filename on the specified device and opening a specified channel (#channel must be an integer in the range 0..32767) to that filename for output.

If Toolkit II is present, OPEN_NEW supports the default data device (see DATAD$), however in any case if the device (or default data device) does not contain a formatted medium, the error ‘not found’ (-7) will be reported. An error will also be reported if the medium is read only.

Without Toolkit II, if the filename already exists, then the error ‘already exists’ will be generated. On the other hand, Toolkit II will show the familiar ‘OK to Overwrite?’ prompt.

Once the channel is open, any attempt to open another channel to that same filename at the same time will report an error ‘In use’.

Example

A simple interactive copying routine:

100 INPUT #0,'COPY :-'!in$!'=>'!out$
110 OPEN_IN #3,in$
120 OPEN_NEW #4,out$
130 REPeat copy_loop
140   IF EOF(#3):EXIT copy_loop
150   a$=INKEY$(#3)
160   PRINT a$;:PRINT #4,a$;
170 END REPeat copy_loop
180 CLOSE #4,#3
190 PRINT #0,'Copying complete'

NOTE 1

The OPEN_NEW command will close a channel which is already open with the same channel number prior to opening the new channel - do not try to OPEN_NEW #0 unless you have read the notes on OPEN!

NOTE 2

If instead of device_filename, another type of device is used, such as scr_, OPEN_NEW has the same effect as OPEN.

NOTE 3

In version 2.05 of Toolkit II, if the filename already exists, the channel may be left open.

NOTE 4

Similar problems exist with OPEN_NEW to those encountered with SAVE when trying to write to a write-protected microdrive cartridge. Unfortunately however, the problem is made worse by the fact that the problem is not revealed when the channel is opened. Instead ‘bad or changed medium’ is only displayed when the file is written to (ie. when 512 characters have been written to the channel, or the channel is CLOSEd).

CROSS-REFERENCE

FOP_NEW is an error trapped function which is equivalent to this command. OPEN_DIR allows you to access directories on drives. OPEN contains a general description of all the open types. OPEN_IN and OPEN_OVER are also linked with this.