sWrite (Function)

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Help / WLanguage / WLanguage functions / Standard functions / Windows functions / Serial/Parallel Ports functions

Miscellaneous
Transmission between two stations using different string formats (Unicode and ANSI)
Using an external library: RXTX
Features specific to Android and Android widget

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sWrite (Function)

In french: sEcrit

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).
Infrared ports are not supported.
Only serial ports are supported.
This function returns information regarding the server.

Example

// Le port COM2 est ouvert
NumPort = sOpen("COM2", 2000, 2000) // Ouverture de COM2
IF NumPort <> 0 THEN
	sMessage is string 
	// Envoi d'un message au buffer de sortie de COM2
	sWrite(NumPort, sMessage)
	// Attendre la fin de l'écriture
	LOOP
		IF sInExitQueue(2) = 0 THEN BREAK
	END
	Info("Fin de l'écriture")
END

Syntax

Syntax not available in Android and Android widget

Writing a character string to the output buffer of a port Hide the details

<Result> = sWrite(<Port number> , <String 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:
Serial port number: 1, 2, 3, ... 32 for COM1, COM2, COM3, ... COM32.
Parallel port number: -1, -2, -3 or -4 for LPT1, LPT2, LPT3 or LPT4.
Infrared port number: 1, 2, 3, ... 32 for IR1, IR2, IR3, ... IR32.
Infrared ports are not supported.
Port identifier returned by sOpen (if this function was called with a port name).
Only this type of parameter is available.

<String to write>: Character string

Character string that must be written into the output buffer.

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:
Serial port number: 1, 2, 3, ... 32 for COM1, COM2, COM3, ... COM32.
Parallel port number: -1, -2, -3 or -4 for LPT1, LPT2, LPT3 or LPT4.
Infrared port number: 1, 2, 3, ... 32 for IR1, IR2, IR3, ... IR32.
Infrared ports are not supported.
Port identifier returned by sOpen (if this function was called with a port name).
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.
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 stations using different string 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)
Format of character strings on the current computer	Write operation (sWrite function)	String in ANSI format	String in UNICODE format
ANSI (PC running Windows for example)	The character string will be in ANSI format	No conversion is required	Conversion required (UnicodeToAnsi)
Unicode	The character string will be in Unicode format	Conversion required (AnsiToUnicode)	No conversion is required

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.

Using an external library: RXTX

In Java, the use of serial and parallel port manipulation functions (functions 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).

You can download the RXTX library and its documentation from the following link: http://users.frii.com/jarvi/rxtx/index.html (link valid at the time of writing).

Attention: Infrared port management not available in Java.

Features specific to Android and Android widget

In Android and Android widget mode, the serial and parallel port functions can be used:

Only on serial (not parallel or infrared) ports.
Only with devices that support the CDC/ACM protocol (Arduino ATmega32U4) and the following USB to serial converter chips:
- FTDI FT232R, FT232H, FT2232H, FT4232H, FT230X, FT231X, FT234XD
- Silabs CP210x
- Qinheng CH340, CH341A
- Prolific PL2303

Business / UI classification: Business Logic

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