NAME

fsync − synchronize a file’s in-core state with that on disk

SYNTAX

fsync(fd)
int fd;

DESCRIPTION

The fsync system call causes all modified data and attributes of fd to be moved to a permanent storage device.  This results in all in-core modified copies of buffers for the associated file to be written to a disk. 

The fsync call should be used by programs which require a file to be in a known state, for example, in building a simple transaction facility.

RETURN VALUE

A 0 value is returned on success.  A −1 value indicates an error. 

DIAGNOSTICS

The fsync call fails if:

[EBADF]
The fd argument is not a valid descriptor. 

[EINVAL]
The fd argument refers to a socket. 

[EIO] An I/O error occurred while reading from or writing to the file system. 

If an error occurs on an asynchronous write over NFS, the error cannot be returned from the close system call.  The error code will be returned on write or fsync. 

SEE ALSO

sync(1), sync(2), update(8)

System Calls