mccalpin@perelandra.cms.udel.edu (John D. McCalpin) (03/08/91)
I am working on a FORTRAN application that needs to sit and wait for certain data files to be completely written. The basic loop is OPEN(in_unit,....) 8888 READ(in_unit,ERR=8888,END=8888) data CLOSE(in_unit) This works fine, but uses up lots of system time that would be better spent by the other process that is supposed to be writing the data! On the Silicon Graphics machines, there is a nice function called 'sginap(i)' which: -- with an argument of 0, will release control to any other process with the same or higher priority; or -- with an argument i>0, will sleep for 'i' clock ticks. The modified code segment: OPEN(in_unit,....) 8888 idummy = sginap(0) READ(in_unit,ERR=8888,END=8888) data CLOSE(in_unit) runs much more efficiently. I cannot use the normal 'sleep()' routines, since the actual latencies involved are much smaller than 1 second, and the OPEN/READ/CLOSE sequence needs to be done several times per second. Is this functionality available in a more standard UNIX call? Does AIX have this functionality? This is important, since I really want to run the application on a network of IBM 320's sharing files via NFS. -- John D. McCalpin mccalpin@perelandra.cms.udel.edu Assistant Professor mccalpin@brahms.udel.edu College of Marine Studies, U. Del. J.MCCALPIN/OMNET