How to return information from Excel to the caller

Question

I start Excel from the command line and my add-on does some work. when it's done, I want to return some info to the caller. At least 0/1 for success failure or better also an optional error-message.

By caller I mean the command or process that started Excel. e.g. in a Windows command script I could call excel like this:

Excel.exe SomeWorkbook.xlsx /p C:\Somedir /e

when you call an executable in Windows, it can return an numeric code or set an error.

in a script you could check the result like this:

if %errorlevel% neq 0 (
    echo some error occurred...
)

MessageBoxes, etc. are no option, because this whole task should be triggered by another application automatically without any user-interaction.

How can we do that?

Answer 1

I ended up using text files: i.e when the add-on finished correctly, it will create an empty file OK.txt and when an error occurred it will create a file named ERR.txt that contains the error-message.

Now it's easy for the calling script to check the result:

• OK.txt exists: everything is fine - delete OK.txt
• no file exists: a fatal error has happened: show a general error message
• ERR.txt exists: an error occured: maybe display the error text (contents of the text-file) to the user, delete ERR.txt

Answer 2

You could use the status bar: Application.StatusBar = “your message here” As far as I know, the message box requires a button to be clicked: macro will wait...