The ST/QL Emulator and SMSQ/E allow you to set up the PRT device so that it mimics the SER, STX or PAR device. This means that programs can be written which merely send their output to the PRT device and it is then up to the user to set the port and options required by the device attached to either the serial or parallel port.
The command PRT_USE allows you to specify both the port and options to be associated with PRT.
It will ignore SER_USE and PAR_USE settings and therefore expects device to be in one of the following forms:
PAR<port><translate><convert><eof> SER<port><parity><handshake><translate><convert><eof> STX<port><parity><handshake><translate><convert><eof>
See the Appendix on drivers for further details.
will cause all attempts to access the PRT device to be re-directed to serial port 1 with Even parity, translation enabled and a form feed being printed at the end of the file.
|Location||Qjump RAMPRT, Trump Card, Gold Card, QXL Card|
Unlike the ST/QL Emulator and SMSQ/E implementations of this command, this version of this command is used to enable you to set up dynamic buffering on serial and parallel ports. The command PRT_USE enables you to connect a buffer to a specified device, altering the description (usage) used to access that buffered device. Initially, the default usage is PRT and the default device is SER which means that any attempt to send output to the PRT device will actually access ser1, using the whole of the available memory as a buffer.
PRT_USE will actually recognise the full device name, allowing it to have a similar effect as the alternative version of this command. For example, the following are both equivalent:
PRT_USE prt,ser1c (On the Gold Card) PRT_BUFF 0: PRT_USE ser1c (Under SMSQ/E)
The PRT device will also allow the same options as the device which it is emulating, for example, the following are both the same (except the latter uses buffered output):
OPEN #3,ser1c PRT_USE prt,ser:OPEN #3,prt1c
If you wish to buffer output on a given device, then you merely need to specify the usage to be the same as the device. For example:
will create buffered output to the serial ports whenever ser is used.
PRT_USE will also allow you to specify the device to be buffered at run-time. This is achieved by leaving the device parameter as an empty string. For example:
allows you to use the device name buff_ser1 to access ser1, buff_par to access the parallel port etc. and all with buffered output.
will return the QL to the normal state after being switched on (ie. only buffered output will occur if the device PRT is used).
If PRT_USE is used to allow background printing, then some characters may be lost (especially if you are using an old serial to parallel converter), if you use a command which stops the QL multitasking (for example FORMAT, LOAD, LBYTES, SBYTES and SAVE).
You can tell when this happens as the printer will stop while the command is being carried out.
See also PRT_ABT. See the other version of this command.