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open_excl(3)          DragonFly Library Functions Manual          open_excl(3)

NAME
       open_excl - open a file for exclusive writing

SYNTAX
       #include <open.h>

       int open_excl(const char *filename);

DESCRIPTION
       open_excl opens the file filename for writing and returns the file
       handle.  The file may not exist before the call to open_excl.  The file
       will be created with mode 0600.

       If there was an error creating the file, open_excl returns -1 and sets
       errno accordingly.

       Since open_excl relies on the O_EXCL flag to open, it does not work
       reliably over NFS (the NFS protocol is broken) and must be emulated
       using a lock file (create a file with a unique file name and link(2) it
       to the lock file.  Then stat the lock file and see if the link count is
       2).

SEE ALSO
       open(2)

                                                                  open_excl(3)