OPEN LPT


Open a printer device

Syntax:
Open Lpt ["[LPT[x]:][Printer_Name][,TITLE=Doc_Title][,EMU=TTY]"] [For Input|Output] as #filenumber

Usage:
Open Lpt "LPT..." as [#]filenumber
or
result = Open Lpt( "LPT..."[,] as [#]filenumber )

Parameters:
x
Specifies a port number. If omitted, output is sent to the system print spooler.
Printer_Name
Name of printer to open. This parameter is ignored on DOS.
TITLE=Doc_Title
Title of the print job as seen by the printer spooler. This parameter is ignored on DOS.
EMU=TTY
Emulation of TTY output on a windows GDI printer, using driver text imaging. This parameter is ignored on DOS and Linux.
For Input|Output
clause is allowed for compatibility, but it is ignored.
filenumber
An unused file number to assign to the device.

Return Value:
A 32 bit Long: 0 is returned if Open Lpt() completed successfully, otherwise a non-zero value is returned to indicate failure.

Description:
Open Lpt opens a connection to a printer device. The connection is treated like a file, so data may be written to the printer using Print and Put # commands.

Any printer attached to the system may be opened with Open Lpt

Open Lpt "LPT:" ... will try to open the default printer on Windows and Linux, and "LPT1:" on DOS.

Lprint will automatically try to open the default printer on Windows and Linux, and "LPT1:" on DOS.

The error code returned by Open Lpt can be checked using Err in the next line. The function version of Open Lpt returns directly the error code as a 32 bit Long.

Platform specific notes:

Windows
The argument EMU=TTY assumes printable ASCII or Unicode text, and applies printer driver text imaging to the input. EMU=TTY also allows the usage of CR, LF, BS, TAB, FF, etc., for virtual print-head movement...even when the printer is a GDI printer and therefore doesn't itself understand these special characters. If ",EMU=TTY" is omitted, the data must be sent in the printer's language (ESC/P, HPGL, PostScript, etc...). Other useful emulation modes aren't supported yet.

Linux
A printer spooler available through lp must be installed to access printers by name or a default printer. Spooler access was tested only with CUPS, but other spoolers may work that are invoked through lp. Port are zero-based on Linux. "LPT1:" corresponds with "/dev/lp0".

The data must be sent in the printer's language (ESC/P, HPGL, PostScript, etc...). Emulation modes aren't supported yet.

DOS
FreeBASIC does not support print spoolers on DOS. Printers must be accessible through "LPTx:".

The data must be sent in the printer's language (ESC/P, HPGL, PostScript, etc...). Emulation modes aren't supported yet.

Examples:
' Send some text to the Windows printer on LPT1:, using driver text imaging.
Open Lpt "LPT1:EMU=TTY" For Output  As #1
Print #1, "Testing!"
Close

' Sends contents of text file test.txt to Windows printer named "ReceiptPrinter"
Dim RptInput As String
Dim PrintFileNum As Integer, RptFileFileNum As Integer

RptFileFileNum = FreeFile
Open "test.txt" For Input As #RptFileFileNum

PrintFileNum = FreeFile
Open Lpt "LPT:ReceiptPrinter,TITLE=ReceiptWinTitle,EMU=TTY" As _
    #PrintFilenum

While (EOF(RptFileFileNum) = 0)
        Line Input #RptFileFileNum, RptInput
        Print #PrintFileNum, RptInput
Wend

Close #PrintFileNum  ' Interestingly, does not require CHR(12).  But if pagination is desired, CHR(12) is the way.

Close #RptFileFileNum

Print "Press any key to end program..."
GetKey

End


'This simple program will print a PostScript file to a PostScript compatible printer.
Dim As UByte FFI, PPO
Dim As String temp

FFI = FreeFile()
Open "sample.ps" For Input Access Read As #FFI
PPO = FreeFile()
Open Lpt "LPT1:" For Output As #PPO
While (EOF(FFI) = 0)
Line Input #FFI, temp
Print #PPO, temp
Wend

Close #FFI
Close #PPO

Print "Printing Completed!"


Dialect Differences:
See also:
Back to File I/O Functions
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