zxcvbob writes:

It would be safer to install a recessed-male plug somewhere instead of
using a dryer outlet. There's a reason double male cords are called
"suicide cords".

But you don't really want the male plug connected to a normal breaker in
the panel, either, because it would become live with exposed hot metal
parts if someone turned the breaker on by accident when the panel was
under utility power. That's at least as suicidal.

The safe way to do this is with the male plug connected to one input of
a transfer switch that is upstream of the main panel. The transfer
switch avoids any possibility of backfeeding, and it also means that the
male plug can never be powered from the utility. It can only receive
power from the generator, and pass it along to the main panel if the
transfer switch is set appropriately.

Dave