Forking and Locks

When a process forks, the child receives a copy of the file descriptors that the parent opened. Locks are not inherited by the child because they are owned by a specific process. The parent and child share a common file pointer for each file. Both processes can try to set locks on the same location in the same file. This problem happens with both lockf(3C) and fcntl(2). If a program holding a record lock forks, the child process should close the file and reopen it to set a new, separate file pointer.