Working Notes: my commonplace notebook for recording & exploring ideas.
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Notes on IPC

• Beej’s guide
• fork consequences
  • ignore SIGHCHLD or wait for children explicitly as far as possible
  • `wait(&child_rv)
• signals: sigaction
  • write is async safe, printf is not
  • volatile vars are okay to alter
• pipes:
  • pipe to open fd to write to & read from
  • dup clones to first available file descriptor
  • limited beyond connected processes
• fifo:
  • named pipe, to allow unrelated processes to grab it
  • mkfifo
  • open blocks till something downstream opens for reading (aside O_NDELAY)
  • handle SIGPIPE to figure out if readers are gone
• file locks:
  • advisory locks that can be checked
  • fcntl
• message queues:
  • mq_overview, sem_overview, shm_overview
  • pretty cool from the manpages, can view what’s going on
• semaphores:
  • sem_overview
• shared memory:
  • shm_overview
• memory mappd files
  • mmap, munmap
• unix sockets
  • sockets communicate over domains
  • socket, bind , recv
  • socketpair

— Kunal