QW Support wrote:

I'm having trouble running the latest LMDB version on iOS 8.1.3

It seems to work with previous versions before SysV semaphores were used.

Now it crashes with SIGSYS on line:

semid = semget(IPC_PRIVATE, 2, mode); (line:4520 file:mdb.c)

Has anyone got this to work?

Sounds like iOS doesn't support SysV semaphores. That's unfortunate. I was hoping we could forget about the POSIX semaphore code but apparently we can't. I suggest you look back through the git history and revert the commit that removed the POSIX semaphore code in your build.

LMDB on iOS is pretty limited already; iOS only supports 2GB of address space even on the 64 bit builds. Apple's quite dishonest here, advertising 64 bit support but not actually delivering any of the advantages of it.