> But this only wins if a child process inheriting an open file also
> inherits copies of any locks held by the parent.  If not, then the
> issue is moot.  Anybody have any idea if file locks work that way?
> Is it portable??

>From RedHat 8.0 manages fork(2):

       #include <sys/types.h>
       #include <unistd.h>

       pid_t fork(void);

       fork  creates a child process that differs from the parent process only
       in its PID and PPID, and in the fact that resource utilizations are set
       to 0.  File locks and pending signals are not inherited.
              ^^^^^^^^^^                     ^^^^^^^^^^^^^^^^^^

And from SunOS 5.8 flock
     Locks are on files, not file  descriptors.   That  is,  file
     descriptors  duplicated  through  dup(2)  or  fork(2) do not
     result in multiple instances of a lock, but rather  multiple
     references to a single lock.  If a process holding a lock on
     a file forks and the child explicitly unlocks the file,  the
     parent  will  lose  its  lock.  Locks are not inherited by a
     child process.

If I understand correctly it says that if parent dies, file is unlocked no
matter if there's children still running?

Antti Haapala

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