Linux / Unix Command: fsync

Command Library

NAME

fsync, fdatasync - synchronize a file's complete in-core state with that on disk  

SYNOPSIS

#include <unistd.h>

int fsync(int fd);

int fdatasync(int fd);  

DESCRIPTION

fsync copies all in-core parts of a file to disk, and waits until the device reports that all parts are on stable storage. It also updates metadata stat information. It does not necessarily ensure that the entry in the directory containing the file has also reached disk. For that an explicit fsync on the file descriptor of the directory is also needed.

fdatasync does the same as fsync but only flushes user data, not the meta data like the mtime or atime.

 

RETURN VALUE

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

ERRORS

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.

 

SEE ALSO

bdflush(2), open(2), sync(2), mount(8), update(8), sync(8)

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