Error: unhandled exception: errno: 9 `Bad file descriptor' [IOError]

[retsyo]

I am using latest cloned&built nim

$ nim
Nim Compiler Version 1.5.1 [Windows: amd64]
Compiled at 2020-12-29
Copyright (c) 2006-2020 by Andreas Rumpf

Example

echo 1

Current Output

when I compile the a.nim with nim c -r --app:gui a.nim, I get an error msgbox

R:\a.nim(1)
a
E\msys64\home\USER\_nim\nim\lib\system\io.nim(791) echoBinSafe
E:\msys64\home\USER\_nim\nim\lib\system\io.nim(156) checkErr
E:\msys64\home\USER\_niminim\lib\system\io.nim(139) raiseEIO
Error: unhandled exception: errno: 9 `'Bad file descriptor` [IOError]

when I compile a.nim as nim c -r a.nim, I see

1

as expected

Expected Output

yes, I know --app:gui means to compile a GUI app without console, so I expect nim c -r --app:gui a.nim runs but without error msgbox. Why do I need this? Because I write some echo xx in my app which are used for debugging. When the app is finished, I need to release a GUI app to the user without console, but I am lazy to remove the echo xx statements.

thanks

[ringabout]

Workaround:
Use nim c -r --app:gui -d:nimLegacyEchoNoRaise

[ringabout]

see #16367

[timotheecour]

#16367 was still correct to raise; -d:nimLegacyEchoNoRaise is indeed usable here, but you probably should use:

template myEcho(args: varargs[untyped]): untyped =
  # adapt if needed so echo still renders at CT using `when nimvm`
  when appType == "gui": discard
  else: echo(args)

(or, if it's meaningful to support, echo at RT with app:gui could be implemented by rendering a window , eg System.Windows.MessageBox https://mcpmag.com/articles/2016/06/09/display-gui-message-boxes-in-powershell.aspx)

[Clyybber]

IMO the change should be reverted, what worth is it raising if you can't display the exception (on platforms where we don't have this messagebox)?
It's only useful if you intend to catch the exception, but since all code that relies on that will be new code, the raising version of echo should be a new proc.

[ringabout]

(or, if it's meaningful to support, echo at RT with app:gui could be implemented by rendering a window , eg System.Windows.MessageBox

no

It is easy to fix. Just adding not defined(guiapp) is enough without reverting original PR.

echo 1

In windows, I got a messagebox and I can catch this exception.

Note that app:gui is specific to Windows
see disable --app:gui for non Windows targets; fixes #2576