What is “lock file”?

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Mark says at https://unix.stackexchange.com/a/467795/




One use for O_EXCL and O_CREAT with open() is to create a simple lock file. If multiple processes try to open the same file with the O_CREAT and O_EXCL flags, one will succeed and the rest will fail. Of course, if the file already exists, for example because a previous process exited without removing the file, none of the subsequent attempts will succeed, so this is not the most robust way to manage a lock.




What does "lock file" mean?



The quote seems to me that the program which creates a lock file should delete it before termination. If so, is a lock file not used for storing meaning data, but for some other purpose?



Thanks.






files io lock






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    Mark says at https://unix.stackexchange.com/a/467795/




    One use for O_EXCL and O_CREAT with open() is to create a simple lock file. If multiple processes try to open the same file with the O_CREAT and O_EXCL flags, one will succeed and the rest will fail. Of course, if the file already exists, for example because a previous process exited without removing the file, none of the subsequent attempts will succeed, so this is not the most robust way to manage a lock.




    What does "lock file" mean?



    The quote seems to me that the program which creates a lock file should delete it before termination. If so, is a lock file not used for storing meaning data, but for some other purpose?



    Thanks.






    files io lock






    share























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      Mark says at https://unix.stackexchange.com/a/467795/




      One use for O_EXCL and O_CREAT with open() is to create a simple lock file. If multiple processes try to open the same file with the O_CREAT and O_EXCL flags, one will succeed and the rest will fail. Of course, if the file already exists, for example because a previous process exited without removing the file, none of the subsequent attempts will succeed, so this is not the most robust way to manage a lock.




      What does "lock file" mean?



      The quote seems to me that the program which creates a lock file should delete it before termination. If so, is a lock file not used for storing meaning data, but for some other purpose?



      Thanks.






      files io lock






      share













      Mark says at https://unix.stackexchange.com/a/467795/




      One use for O_EXCL and O_CREAT with open() is to create a simple lock file. If multiple processes try to open the same file with the O_CREAT and O_EXCL flags, one will succeed and the rest will fail. Of course, if the file already exists, for example because a previous process exited without removing the file, none of the subsequent attempts will succeed, so this is not the most robust way to manage a lock.




      What does "lock file" mean?



      The quote seems to me that the program which creates a lock file should delete it before termination. If so, is a lock file not used for storing meaning data, but for some other purpose?



      Thanks.






      files io lock




      files io lock





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