Most apps on Windows I use at least doesn't have that, I need to reopen apps after a reboot (unless they auto-launch at all boots) and the windows definitively doesn't stay in the same position and have the same contents as before the reboot.
I haven't used Linux desktop lately though, but I'm not aware that they had an API for that.
Ah, you mean session restoration rather than reliable sleep.
You're probably right. Linux desktops environments (or at least some of them) used to have an attempt at something like that, but I think it only worked for applications that made an effort towards it, and I personally haven't even tried to see how or if that works nowadays.
Suspend to RAM and hibernation fill that hole for me, although it's admirable if someone has been able to properly solve the problem of restoring the session after a full reboot.
I haven't used Linux desktop lately though, but I'm not aware that they had an API for that.