FSYNC(2) MidnightBSD System Calls Manual FSYNC(2)

NAME

fsync — synchronise changes to a file

LIBRARY

Standard C Library (libc, −lc)

SYNOPSIS

#include <unistd.h>

int

fsync(int fd);

DESCRIPTION

The fsync() system call 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.

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

RETURN VALUES

The fsync() function returns the value 0 if successful; otherwise the value −1 is returned and the global variable errno is set to indicate the error.

ERRORS

The fsync() fails if:

[EBADF]

The fd argument is not a valid descriptor.

[EINVAL]

The fd argument 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), syncer(4), sync(8)

HISTORY

The fsync() system call appeared in 4.2BSD.

MidnightBSD 0.3 June 4, 1993 MidnightBSD 0.3