IOException 104


Someone is reporting an error when running (debugging in IDE) my gHMTL Desktop editor demo project (downloadable here).
The error occurs on a mac running macOS 10.13.6 and Xojo 2018r1.1.

Error message is IOException (Error Number 104), probably on a TextOutputStream.Create.

I’m running (debugging in IDE) the same demo project on my own mac, same macOS and Xojo versions, without any problem.

I can reproduce the same error by setting the privileges of folder containing the demo app to read-only. But the developer reporting the error checked and has read/write privileges, so that’s not the reason.

Does someone know:

  • what’s exactly the IOException error 104 (I didn’t find any NSError error 104 in Apple doc) ?
  • what could cause the same project to run perfectly on my mac and not on another mac with exactly same OS and Xojo versions ?

Rem: the developer says he has no plugins installed, I installed a fresh Xojo 2018r1.1 with no plugins to have the same config.

Any ideas welcome.

Thanks !


104 = File In Use

Hi Greg,

The file is created by the app, within the app folder and it’s very unlikely that it could be “in use” by another process.

However, the offending method can be called multiple times (by different events) and it seems that the method never fails the 1st time.
Basically and summarized all the method does is:

Dim t As TextOutputStream Dim f As FolderItem = GetFolderItem("").Child("temp.text" ) If f <> Nil then t = TextOutputStream.Create(f) ' create or replace t.Write(sometext) t.Close End If

The app uses no thread.
Could it be that an event (or the underlying OS calls) would keep the file “in use” and block the next one ?