ExtraTopLevelOperators.eprintfn<'T> Function (F#)

Print to stderr using the given format, and add a newline.

Namespace/Module Path: Microsoft.FSharp.Core.ExtraTopLevelOperators

Assembly: FSharp.Core (in FSharp.Core.dll)

// Signature:
eprintfn : TextWriterFormat<'T> -> 'T

// Usage:
eprintfn format

This function is named PrintFormatLineToError in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.

The following code example illustrates the use of eprintfn.

let maxValue = 10
let function1 x =
   if (x > maxValue) then
       eprintfn "Error: the input %d exceeds the maximum value, %d." x maxValue
   else
       printfn "Success!"
function1 1
function1 11

Output

Success!
Error: the input 11 exceeds the maximum value 10.

Windows 8, Windows 7, Windows Server 2012, Windows Server 2008 R2

F# Core Library Versions

Supported in: 2.0, 4.0

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