OPEN ERR

• Source: https://www.freebasic.net/wiki/wikka.php?wakka=KeyPgOpenErr
• Last revised: 2023-06-24

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Opens both the standard input (stdin) and standard error (stderr) streams, using it as if it were file operations.

Syntax

` Open Err [for mode] as [#]filenumber as long

`

Usage

Open Err [for mode] as [#]filenumber

or

result = Open Err( [for mode[,]] as [#]filenumber )

Parameters

mode

Ignored.

filenumber

An unused file number.

Return Value

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

Description

This command opens stdin to read from and stderr to write to the console allowing read and write operations with normal file commands.

stderr is an output stream different from stdout allowing error messages to be redirected separately from the main console output.

The normal console commands, such as Color and Locate, do not work in this mode, because they do not accept a file number.

The TAB keyword, regardless of the given column number, is always interpreted as a simple comma (,) (next output will take place at the next 14 column boundary).

The [For Input|Output] mode is allowed for compatibility, but is ignored.

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

Runtime errors: Open Err throws one of the following runtime errors:

(1) Illegal function call

• Filenumber was not free at the time. use Freefile to ensure that filenumber is free.

Examples

start GeSHi

Dim a As String
Open Err For Input  As #1
Print #1,"Please write something and press ENTER"
Line Input #1, a
Print #1, "You wrote"; a
Close
Sleep

end GeSHi

Differences from QB

• New to FreeBASIC

See also

• Open

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