5 POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9699919799/functions/fsync.html}
9 Portability problems fixed by Gnulib:
12 This function is missing on some platforms:
16 Portability problems not fixed by Gnulib:
19 If the argument is a read-only file descriptor, this function fails
20 with @code{EBADF} on some platforms: