fsync - Writes changes in a file to permanent storage
int fsync (
int fildes );
Interfaces documented on this reference page conform to industry standards
Refer to the standards(5) reference page for more information about indus-
try standards and associated tags.
Specifies a valid open file descriptor.
The fsync function causes system buffers containing a file's modified data
and attributes to be written to permanent storage. The fsync function does
not return until the operation has been completed. The fsync function pro-
vides file integrity, ensuring that data and file attribute information in
permanent storage is identical to data and file attribute information in
The file identified by the fildes parameter must be open for writing when
the fsync function is issued or the call will fail.
Upon successful completion, the fsync function returns a value of 0 (zero).
If the fsync function fails, a value of -1 is returned and errno is set to
indicate the error. If fsync fails, outstanding I/O operations are not
guaranteed to have been completed.
If the fsync function fails, errno may be set to one of the following
[EBADF] The fildes parameter is not a valid file descriptor.
[EINVAL] The fildes parameter does not refer to a file on which this
operation is possible.
If any queued I/O operations fail, the fsync function returns error condi-
tions defined for the read and write functions.
Functions: aio_fsync(2), fdatasync(2), fcntl(2), open(2), read(2), sync(2),