Wiki source for KeyPgOpenErr


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{{fbdoc item="title" value="OPEN ERR"}}----
Opens both the standard input (//stdin//) and standard error (//stderr//) streams for file operations.

{{fbdoc item="syntax"}}##
**[[KeyPgOpen|Open]] Err** [for //mode//] [[KeyPgAs|as]] [#]//filenumber// [[KeyPgAs|as]] [[KeyPgLong|long]]
##
{{fbdoc item="usage"}}##
**Open Err** [for //mode//] as [#]//filenumber//
//or//
//result// = **Open Err**( [for //mode//[,]] as [#]//filenumber// )
##
{{fbdoc item="param"}}
##//mode//##
Ignored.
##//filenumber//##
An unused file number.

{{fbdoc item="ret"}}
A 32 bit ##[[KeyPgLong|Long]]##: a zero is returned if ##**Open Err()**## completed successfully, otherwise a non-zero value is returned to indicate failure.

{{fbdoc item="desc"}}
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 ##[[KeyPgColor|Color]]## and ##[[KeyPgLocate|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 ##[[KeyPgErr|Err]]## in the next line. The function version of ##**Open Err**## returns directly the error code as a 32 bit ##[[KeyPgLong|Long]]##.

**Runtime errors:**
##**Open Err**## throws one of the following [[ProPgErrorHandling|runtime errors]]:

//(##1##) Illegal function call//
- ##//Filenumber//## was not free at the time. use ##[[KeyPgFreefile|Freefile]]## to ensure that ##//filenumber//## is free.

{{fbdoc item="ex"}}
{{fbdoc item="filename" value="examples/manual/fileio/openerr.bas"}}%%(freebasic)
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
%%

{{fbdoc item="diff"}}
- New to ""FreeBASIC""

{{fbdoc item="see"}}
- ##[[KeyPgOpen|Open]]##

{{fbdoc item="back" value="CatPgFile|File I/O Functions"}}
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