Overhead for always having all MIDI devices open?

I’m just wondering if anyone knows offhand if the overhead for MIDI devices is substantial. In other words, if I open all the available devices when my application starts up, and leave them open until the application exits, will they eat up a lot of CPU?

I’m asking because I’d prefer to be always monitoring any MIDI messages on any device, but only if it’s not too resource-intensive.

Thanks for any advice.

That’s what I’m doing , and there is no overhead.

MIDI’s a very slow connection - one cable can only transmit about 1000 events a second, and it’s rare to get even 10% of that. And as a serial protocol, if nothing happens then your code won’t even wake up.

The overhead should be “too small to notice”. Don’t worry about it.