FSYNC

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

#include <unistd.h>

int fsync(int fd);

fsync copies all in-core parts of a file to disk.

In some applications, fdatasync is a more efficient alternative to fsync.

On success, zero is returned. On error, −1 is returned, and errno is set appropriately.

EBADF

fd is not a valid file descriptor open for writing.

EROFS, EINVAL

fd is bound to a special file which does not support synchronization.

EIO

An error occurred during synchronization.

POSIX.1b (formerly POSIX.4)

bdflush(2), fdatasync(2), sync(2), update(8), sync(8)