https://community.hpe.com/t5/operating-system-linux/exclusive-access-on-files/m-p/3622664#M104722 Is there any way in C to open a file (on HP-UX) having an exclusive access for writing?<BR />I mean I have just one process that have to write in this file while other programs can only read. Is it possible?<BR />On other Unix flavour there is the flag “O_RSHARE” for the “open” api. On HP?<BR /><BR />Thanks.<BR /> Fri, 09 Sep 2005 10:02:34 GMT Marco Salvi 2005-09-09T10:02:34Z https://community.hpe.com/t5/operating-system-linux/exclusive-access-on-files/m-p/3622664#M104722 Is there any way in C to open a file (on HP-UX) having an exclusive access for writing?<BR />I mean I have just one process that have to write in this file while other programs can only read. Is it possible?<BR />On other Unix flavour there is the flag “O_RSHARE” for the “open” api. On HP?<BR /><BR />Thanks.<BR /> Fri, 09 Sep 2005 10:02:34 GMT https://community.hpe.com/t5/operating-system-linux/exclusive-access-on-files/m-p/3622664#M104722 Marco Salvi 2005-09-09T10:02:34Z https://community.hpe.com/t5/operating-system-linux/exclusive-access-on-files/m-p/3622665#M104723 There is no direct equivalent but you can use<BR />lockf() or fcntl() to do this. If you set the setgid bit on the data file then the locks become mandatory rather than advisory.<BR />A far simpler solution and one that would be portable across all flavors of UNIX is to set the permissions to 640 or 644 and the "writer" process would have the effective UID of the owner of the file. Fri, 09 Sep 2005 10:32:24 GMT https://community.hpe.com/t5/operating-system-linux/exclusive-access-on-files/m-p/3622665#M104723 A. Clay Stephenson 2005-09-09T10:32:24Z