Revision [21757]
This is an old revision of KeyPgOpenErr made by fxm on 2017-05-25 00:12:21.
OPEN ERR
Opens both the standard input (stdin) and standard error (stderr) streams for file operations.
Syntax:
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 [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.
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 [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
(1) Illegal function call
- Filenumber was not free at the time. use Freefile to ensure that filenumber is free.
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
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
Differences from QB:
- New to FreeBASIC
See also:
Back to File I/O Functions
