ipc_*, ipc, flow: Port them beyond Linux/x86-64 - macOS, ARM64; Windows. (No *BSD - due to no capnp) about ipc HOT 3 OPEN

Missed one. This snippet pretty much covers it:

#ifdef FLOW_OS_WIN
static_assert(false, "Design of Permissions_level assumes a POSIX-y security model with users and groups; "
                       "we have not yet considered whether it can apply to Windows in its current form.");
#endif

• macOS: Should be fine.
• Windows: Well, see above. S_USER_ACCESS and S_GROUP_ACCESS, to begin with, assume a user/group-based security model - unsure how it works in Windows in the meantime. If it does map cleanly enough, then all instances where a Permissions_level is translated into a specific Permissions value (the POSIX RWXRWXRWC thing) have to be coded appropriately for Windows also. (At a glance, Boost.interprocess permissions class has some simple notion of Windows permissions. There is a void* involved and... stuff.)

from ipc.

A note from delightful HackerNews thread, by user rurban:

I also went this route and came to the very same conclusions. Cap'n proto for fast reading, SHM for shared data, simple short messaging, just everything in C.
My only problem is MacOS with its too small default SHM buffers, you need to enhance them. Most solutions need a reboot, but a simple setter is enough. Like sudo sysctl -w kern.sysv.shmmax=16777216

Details unclear at the moment (to me) but reminder to look into macOS's and Windows's SHM size limits in general at least. (Certainly they were a "thing" for SHM-classic in Linux, much less so in SHM-jemalloc.)

EDIT: Oh. System V. We use the modern POSIX API. This is probably irrelevant as written. But there may be other such limits applicable, as in Linux.

from ipc.

Let's just link the HackerNews thread here - it'll be good to refer to some notes there. E.g., iceoryx guys indicate Windows porting might not be as simple (not that it looks that simply) as the above might indicate. Point is, comb through this when working on it. https://news.ycombinator.com/item?id=40028118

from ipc.