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Help / WLanguage / WLanguage functions / Standard functions / Windows functions / Serial/Parallel Ports functions
  • Miscellaneous
  • Transmission between two computers that use character strings in different formats (UNICODE and ANSI)
  • Using an external library: RXTX
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Stored procedures
Writes a character string to the output buffer of the specified serial port, parallel port or infrared port. The end of writing can be checked by sInExitQueue.
Remarks:
  • The port must be opened beforehand (sOpen).
  • Java Infrared ports are not supported.
  • Linux Only serial ports are supported.
Example
// The COM2 port is opened
PortNum = sOpen("COM2", 2000, 2000) // Open COM2
IF PortNum <> 0 THEN
sMessage is string
// Send a message to the output buffer of COM2
sWrite(PortNum, sMessage)
// Wait for the end of the write operation
LOOP
IF sInExitQueue(2) = 0 THEN BREAK
END
Info("End of write operation")
END
Syntax

Writing a buffer into the output buffer of a port Hide the details

<Result> = sWrite(<Port number> , <Buffer to write>)
<Result>: Integer
  • Number of characters written,
  • 0 if timeout is over and if the writing was not performed.
<Port number>: Integer
Identifier of the port used:
  • Port number:
    • Number of the serial port: 1, 2, 3, ... 32 for COM1, COM2, COM3, ... COM32.
    • Number of the parallel port: -1, -2, -3 or -4 for LPT1, LPT2, LPT3 or LPT4.
    • Number of the infrared port: 1, 2, 3, ... 32 for IR1, IR2, IR3, ... IR32.
      Java Infrared ports are not supported.
  • Port identifier returned by sOpen (if this function was called with a port name).
    Linux Only this type of parameter is available.
<Buffer to write>: Buffer
Buffer that must be written into the output buffer.
Remarks

Miscellaneous

  • sOpen has no effect if the port was not opened by sWrite.
  • A 32-bit application is locked during the duration of the transfer. To avoid this lock, the timeout between two write operations must be specified in sOpen. When the timeout is over and if the writing was not performed, sWrite returns 0.
    Java sWrite is a blocking function during the transfer even if a timeout was specified in sOpen.
  • The time required to transfer the string depends on the transmission speed.
  • The string or the buffer is automatically transferred.
  • WLanguage does not support control signals.
  • The time to wait for a character to be read or written is specified with sOpen.
    • If this time is set to 1s when reading 1024 bytes, the waiting time will be 1024s.
    • If this time is set to "-1s" when reading 1024 bytes, the waiting time will be 1s.
    This prevents lock problems when reading from or writing to the print port.

Transmission between two computers that use character strings in different formats (UNICODE and ANSI)

Some conversions are required to perform a transmission between two computers that use different formats of character strings (Windows (ANSI) and Windows Mobile (UNICODE) for example):
Format of character strings on the current computer
Write operation
(sWrite function)
Read operation
(sRead)
String in ANSI format
String in UNICODE format
ANSI
(PC running Windows for example)
The character string will be in ANSI formatNo conversion is requiredConversion required (UnicodeToAnsi)
UNICODEThe character string will be in UNICODE formatConversion required (AnsiToUnicode)No conversion is required
Linux Special case for Linux:
  • Only serial ports can be opened and initialized.
  • By default, users do not have access to serial ports. It is necessary to grant them specific rights to manage serial ports.
Java

Using an external library: RXTX

In Java, the use of functions for handling the serial and parallel ports (sOpen, sWrite, sRead, ...) requires the presence of an external library: RXTX.
This library includes a Jar archive and one or more native libraries that depend on the operating system on which the application is run. To use these functions:
  • the Jar archive (RXTXComm.jar) must:
    • be found in the same directory as the Java application generated by WINDEV,
    • be found in the execution classpath of the application,
    • be directly included in the generated application (from the wizard for Java generation).
  • the native libraries corresponding to the operating system on which the application is run must be found:
    • in the same directory as the Java application generated by WINDEV,
    • in the path of the application libraries (librarypath).
The RXTX library and its documentation can be downloaded from: http://users.frii.com/jarvi/rxtx/index.html (link valid at the time this documentation was published).
Caution: The management of infrared ports is not available in Java.
Business / UI classification: Business Logic
Component: wd290com.dll
Minimum version required
  • Version 9
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Last update: 07/16/2022

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