There are two things: SysV IPC and POSIX IPC, both of which have message queues. In the SysV case this feature probably made sense because it was designed at a time when BSD sockets were not yet the universaly accepted API. POSIX equivalent probably exists mostly for completeness.
One might say that the whole of POSIX IPC is simply SysV IPC with sane and "unix-like" API (ie. names instead of "IPC keys").
One of the problems with POSIX IPC is that you cannot really use it if you want to be portable, because on BSD and derived systems the implementation is best described as also existing only for completeness.
One might say that the whole of POSIX IPC is simply SysV IPC with sane and "unix-like" API (ie. names instead of "IPC keys").
One of the problems with POSIX IPC is that you cannot really use it if you want to be portable, because on BSD and derived systems the implementation is best described as also existing only for completeness.