Thank you DMac. I do'nt have a win8.x computer.
I am just thinking about upgrading from win7 to win10, and that could in fact be a downgrading !
About the bug, I understand that the AllocConsole did not work, or more precisely, dit not initialize correctly so that further standard I/O crashed.
My question: was it a problem with _cprintf (or _cwprintf) or in other I/O functions?
Thank you for this deep investigation.