fsync

Purpose

     Writes changes in a file to permanent storage.

Syntax

     int fsync (fildes)
     int fildes;

Description

     The fsync  system call  causes all  modified data  in the
     file open on fildes to be saved to permanent storage.  If
     Distributed Services  is installed  on your  system, this
     file can reside  on another node.  If the  file is mapped
     onto a  segment in read-write  mode, then it is  saved to
     permanent storage.  If the  file is mapped copy-on-write,
     then the  pages of  the file that  have been  changed are
     saved to permanent storage.   Saving to permanent storage
     is sometimes called a commit operation.

     An fsync system call can be issued by a process executing
     at the node  on which the file is stored  or by a process
     executing at another  node.  In either case,  the file is
     written to permanent  storage at the node  that holds the
     file.

     In AIX, the file identified  by the fildes parameter must
     be open when the fsync system  call is issued or the call
     fails.

Return Value

     Upon successful  completion, fsync returns a  value of 0.
     If fsync  fails, a value of  -1 is returned and  errno is
     set to indicate the error.

Diagnostics

     The fsync  system call fails if  one or more of  the fol-
     lowing are true:

     EIO        I/O error.

     EBADF      fildes is not a valid file descriptor open for
                writing.

     If  Distributed Services  is  installed  on your  system,
     fsync can also  fail if one or more of  the following are
     true:

     EDIST         The   server   has  blocked   new   inbound
                   requests.

     EDIST         Outbound requests are currently blocked.

     EAGAIN        The  server  is  too  busy  to  accept  the
                   request.

     ENOMEM        Either  this node  or the  server does  not
                   have enough memory available to service the
                   request.

     EBADCONNECT   An attempt to use  an existing network con-
                   nection with a remote node failed.

Related Information

     In this book:  "sync."