Connect another mac as secondary display

I have two macbooks:

• MacBook Pro 2012
• MacBook Pro 2017 with touchbar

Recently I've got an idea to use 2012 as a secondary display. I don't completely understand whether it's possible or not, the only info I found on this is https://www.macobserver.com/tips/how-to/imac-secondary-display/ It's said that this is possible if your second mac has thunderbolt or mini display ports. My 2012 does have it (mini display port). So let's consider it's possible.

It's said I need mini display to usb-c adapter. It's ok but not quite cheap. So finally we reached my question. I already have minidisplay to hdmi adapter. Now I'm wondering is it going to work if I purchase usb-c to hdmi adapter (since it's twice cheaper) and try to connect both adapters to each other?

Solution 1:

No.

Unless explicitly mentioned in the official specifications for the machine, it can't. For this machine it is https://support.apple.com/kb/sp649

You might find Synergy an interesting alternative as it allows you to use both machines at once. https://symless.com/synergy

Solution 2:

Yes. There’s product called Luna Display that a hardware solution that allows you to use a Mac or an iPad as a secondary display.

Use any Mac as a second display — perfect for anyone with multiple Macs. It also works on older Mac models

I’ve personally seen this work - I wouldn’t use it for gaming, but as a secondary display it’s pretty good.

What you were looking at in the linked article is called Target Display Mode and you need a supported iMac to make that work.