I am running Gretl 2021d for Windows. If I place a PDF file Test.pdf in C:/temp,define the string

string command = "C:/temp/Test.pdf"and run the command

! "@command"

the PDF will correctly open, but it takes a long time.

If I run the command

launch "@command"

I get the message

I take it from the manual that both commands should do the same, the first one asynchronously, the second synchronously.

If I use a text file Test.txt, it  opens without delay in the first case but gives the error message in the second.

Maybe I missed something. Not important, but may be worth mentioning.

Cheers

Ekkehart