NAME

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

SYNOPSIS

fsync(fd)
int fd;

DESCRIPTION

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

Fsync 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. 

ERRORS

The fsync fails if:

[EBADF] Fd is not a valid descriptor. 

[EINVAL] Fd refers to a socket, not to a file. 

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

SEE ALSO

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

BUGS

The current implementation of this call is expensive for large files. 

4BSD