sync(S) 6 January 1993 sync(S) Name sync - update super block Syntax cc ... -lc void sync () Description The sync system call causes all information in memory that should be on disk to be written out. This includes modified super blocks, modified inodes, and delayed block I/O. It should be used by programs which examine a filesystem, for example, fsck, df, and so on. It is mandatory before a reboot. The writing, although scheduled, is not necessarily complete upon return from sync. Standards conformance sync is conformant with: AT&T SVID Issue 2; however, this routine has been withdrawn from XPG3.