ONLINE HELP
 WINDEVWEBDEV AND WINDEV MOBILE

Help / WLanguage / WLanguage functions / Standard functions / External file functions
  • Handling errors
  • Position in the file
WINDEV
WindowsLinuxUniversal Windows 10 AppJavaReports and QueriesUser code (UMC)
WEBDEV
WindowsLinuxPHPWEBDEV - Browser code
WINDEV Mobile
AndroidAndroid Widget iPhone/iPadIOS WidgetApple WatchMac CatalystUniversal Windows 10 App
Others
Stored procedures
Reads a line in an external file.
Syntax

Reading a file line by line Hide the details

<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.
Remark: A line ends with a CR character (Carriage Return).
<File used>: Integer or DiskFile variable
<Separator>: Character string
Separator used between the lines. The default separator is the Carriage Return (CR).
New in version 2024
iPhone/iPadIOS Widget

Reading a file line by line using a procedure Hide the details

<Result> = fReadLine(<File used> , <WLanguage procedure> [, <Separator>])
<Result>: Integer
Number of lines read.
Remark: A line ends with a CR character (Carriage Return).
<File used>: Integer or DiskFile variable
<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).
Remarks

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.
Related Examples:
Handling text files Unit examples (WINDEV): Handling text files
[ + ] Handling "text" files with WINDEV:
- Create a text file
- Write into a text file
- Read in a text file
Handling text files Unit examples (WEBDEV): Handling text files
[ + ] This example explains how to handle "non HFSQL" files with WEBDEV and it allows you to:
- Create a text file
- Write into a text file
- Read in a text file
Handling text files Unit examples (WINDEV Mobile): Handling text files
[ + ] Handling external "text" files:
- Create a text file
- Write into a text file
- Read in a text file
Business / UI classification: Business Logic
Component: wd290std.dll
Minimum version required
  • Version 9
This page is also available for…
Comments
Click [Add] to post a comment

Last update: 10/02/2023

Send a report | Local help