File::Sync - Perl access to fsync() and sync() function calls
use File::Sync qw(fsync sync); sync(); fsync(\*FILEHANDLE) or die "fsync: $!"; # and if fdatasync() is available on your system: fdatasync($fh) or die "fdatasync: $!"; use File::Sync qw(fsync); use FileHandle; $fh = new FileHandle("> /tmp/foo") or die "new FileHandle: $!"; ... $fh->fsync() or die "fsync: $!";
The fsync() function takes a Perl file handle as its only argument, and passes its fileno() to the C function fsync(). It returns undef on failure, or true on success. fdatasync() is identical in return value, but it calls C fdatasync() instead of fsync(), synchronizing only the data in the file, not the metadata.
The fsync_fd() function is used internally by fsync(); it takes a file descriptor as its only argument.
The sync() function is identical to the C function sync().
This module does not export any methods by default, but fsync() is made available as a method of the FileHandle class. Note carefully that as of 0.11, we no longer clobber anything in IO::Handle. You can replace any calls to IO::Handle::fsync() with IO::Handle::sync(): https://rt.cpan.org/Public/Bug/Display.html?id=50418
Doing fsync() if the stdio buffers aren't flushed (with
$| or the autoflush method) is probably pointless.
Calling sync() too often on a multi-user system is slightly antisocial.
Carey Evans <firstname.lastname@example.org>
perl(1), fsync(2), sync(2), perlvar(1)