Quoth Muthuselvan Sivam: > We're having a function call fork_dispatcher inside a function loop() in > the avahi-autoip main.c file, which will create a child process. This > child will create a pipe to read the IPv4LL address from the parent, > which writes the address, interface name etc, into this pipe. Since our > child (created by vfork) is currently running and waiting in fread (a > blocking call), it is not giving space to the parent to write the data, > which the child expects. > > In No-MMU systems there is no fork, hence we have to use vfork, which > will block the parent untill child calls _exit.
To get "real" fork behaviour out of vfork (such that both parent and child are running simultaneously), you must make the child process call one of the exec functions (usually as soon as possible after the vfork). Typically, you would re-exec the same binary with a special command-line parameter telling it to perform the child task workload instead of normal operation. Or to save a bit of memory (especially if the child task is simple), execute a separate helper binary instead. Note however that after the exec the child process will have its own clean memory space, so you can't have it inherit state from the parent that way; you'll either need to pass anything required via the command line or use IPC mechanisms such as pipes or explicit shared-memory blocks. _______________________________________________ uClinux-dev mailing list uClinux-dev@uclinux.org http://mailman.uclinux.org/mailman/listinfo/uclinux-dev This message was resent by uclinux-dev@uclinux.org To unsubscribe see: http://mailman.uclinux.org/mailman/options/uclinux-dev
