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Open Err

Paul Squires edited this page Oct 19, 2026 · 2 revisions

Home › File I/O Functions › Open Err

Open Err

Opens standard input and standard error on a file number, to use like a file.

Syntax

Open Err [for mode] As [#]filenumber As Long

Parameters

  • mode
  • filenumber

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

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.

Remarks

Usage

Open Err [for mode] as [#]filenumber

or

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

Differences from QB

  • New to FreeBASIC

See also

Examples

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

Category: File I/O Functions
Kind: keyword


Reproduced from the FreeBASIC Wiki Manual under the GNU Free Documentation License 1.3 — with no Invariant Sections, no Front-Cover Texts and no Back-Cover Texts. Copyright © the FreeBASIC project and wiki contributors. See License.

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