ISREDIRECTED


Checks whether stdin or stdout is redirected to a file

Syntax:
declare function IsRedirected ( byval is_input as long = 0 ) as long

Usage:
#include "fbio.bi"
result = IsRedirected( is_input )

Parameters:
is_input
A long indicating the type of information to return.

Return Value:
Returns non-zero (-1) if stdin or stdout is redirected, otherwise returns zero (0).

Description:
IsRedirected checks whether stdin or stdout is redirected to a file, instead of being connected to the console/terminal as usual.

If is_input is equal to non-zero (-1), IsRedirected checks stdin.
If is_input is equal to zero (0), IsRedirected checks stdout.

Examples:
'' A Windows based example, just for the use principle
'' Self-sufficient example, using his own .exe file as dummy input file for stdin redirection

#include "fbio.bi"

'' Quotation marks wrapping for compatibility with spaces in path name
Dim As String pathExe = """" & ExePath & """"
Dim As String fileExe = Mid(Command(0), Instrrev(Command(0), "\") + 1)
Dim As String redirection = " < """ & Command(0)
If LCase(Right(Command(0), 4)) = ".exe" Then
  redirection &= """"
Else
  redirection &= ".exe"""
End If

If Command() = "" Then  '' First process without stdin redirection
  '' Check stdin redirection
  Print "First process without stdin redirection: IsRedirected(-1) = "; Isredirected(-1)
  '' Creation of asynchronous second process with stdin redirected from file.exe
  Shell("start /d " & pathExe & " /b " & fileExe & redirection & " secondprocess")
  '' Waiting for termination of asynchronous second process
  Sleep
ElseIf Command() = "secondprocess" Then  '' Second process with stdin redirection
  '' Check stdin redirection
  Print "Second process with stdin redirection  : IsRedirected(-1) = "; Isredirected(-1)
End If


Differences from QB:
See also:
Back to Operating System Functions
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