fReadLine (Function)

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Ayuda / WLanguage / Funciones WLanguage / Funciones estándar / Funciones de archivos externos

Handling errors
Position in the file
ANSI/Unicode management

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fReadLine (Function)

Reads a line in an external file.

In this version, it is only possible to read lines in external files in ANSI format.

Ejemplo

Ver ejemplos adicionales

// Open an external file
FileID is int
ResRead is string
FileID = fOpen("C:\MyDirectories\File.txt", foReadWrite)
IF FileID <> -1 THEN
	// Read a line in this file
	ResRead = fReadLine(FileID)
	...
END

// Open an external file
MyTextFile is DiskFile
ResRead is string
MyTextFile = fOpen("C:\MyDirectories\File.txt", foReadWrite)
IF NOT ErrorOccurred THEN
	// Read a line in this file
	ResRead = fReadLine(MyTextFile)
	...
END

Sintaxis

Reading a file line by line Ocultar los detalles

<Result> = fReadLine(<File used> [, <Separator>])

<Result>: Character string or Unicode character string

Line read in an external file.
EOT constant if the end of file has been reached.
Empty string ("") if an error occurred. In this case, the ErrorOccurred variable is set to True.
Note: A line ends with a carriage return (CR).
This parameter must be a character string.

<File used>: Integer or DiskFile variable

Identifier of the file to use, defined by fOpen or fCreate.
Name of the DiskFile variable initialized with fOpen or fCreate.
Not available.
This parameter must be a variant.

<Separator>: Character string

Separator used between the lines. The default separator is the Carriage Return (CR).
This parameter is not available. The separator used is the Carriage return (CR).

Reading a file line by line using a procedure Ocultar los detalles

<Result> = fReadLine(<File used> , <WLanguage procedure> [, <Separator>])

<Result>: Integer

Number of lines read.
Note: A line ends with a carriage return (CR).

<File used>: Integer or DiskFile variable

Identifier of the file to use, defined by fOpen or fCreate.
Name of the DiskFile variable initialized with fOpen or fCreate.
Not available.
This parameter must be a variant.

<WLanguage procedure>: Procedure name

Name of the WLanguage procedure ("callback") called for each line read in the file. This procedure is used to manipulate the current line. For more details on this procedure, see Parameters of the procedure used by fReadLine.

<Separator>: Character string

Separator used between the lines. The default separator is the Carriage Return (CR).
This parameter is not available. The separator used is the Carriage return (CR).

Observaciones

Handling errors

fReadLine throws an error in the following cases:

the file is not opened,
the file is not accessible in read mode,
the file is locked by another computer or by another application. fUnlock is used to unlock an external file.

Position in the file

When opening a file, the current position corresponds to:

the first file byte (by default),
the last byte of the file is the file is opened in "addition" mode (foAdd constant).

This position can be modified by fSeek.

fReadLine reads the specified elements from the current position. Once fReadLine has been executed, the current position is set to the last byte read. fReadLine returns the EOT constant if the end of the file has been reached.

ANSI/Unicode management

The fReadLine function reads:

a Unicode string in a Unicode file.
an Ansi string in an Ansi file.

The file is created or opened with fCreate/fOpen by specifying the file type.

Depending on the format of the external file used, some conversions are required once a character string was read in an external file:


	Current computer	External file in ANSI format (fOpen or fCreate associated with the foAnsi constant)	External file in Unicode format (fOpen or fCreate associated with the foUnicode constant)
fReadLine function	PC running Windows	Read operation in ANSI format Can be converted to Unicode using AnsiToUnicode function
	Mobile	Reading in Unicode format Conversion to ANSI possible with UnicodeToAnsi

Note If the result of the fReadLine function of an ANSI file is assigned to a Unicode string (and vice versa), the conversion will be implicitly performed.

For more details, see Unicode management

Clasificación Lógica de negocio / UI: Lógica de negocio

Componente: wd300std.dll

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Versión mínima requerida

Versión 9

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Última modificación: 28/03/2025

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