FSYNC Section: Linux Programmer's Manual (2) Updated: 2025-04-13 Index   NAME fsync - synchronize a file's complete in-core state with that on disk   SYNOPSIS #include <unistd.h> int fsync(int fd);   DESCRIPTION fsync copies all in-core parts of a file to disk. In some applications, fdatasync is a more efficient alternative to fsync.   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.   CONFORMING TO POSIX.1b (formerly POSIX.4)   SEE ALSO   Index NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO SEE ALSO This document was created by using the manual pages. Time: 11:56:05 GMT, March 24, 2025