Function fdFlush (fd:Longint) : boolean;
fdflush flushes the Linux kernel file buffer, so the file is actually written to disk. This is NOT the same as the internal buffer, maintained by Free Pascal.
The function returns True if the call was successful, false if an error occurred.
Errors are returned in LinuxError.
fdOpen, fdClose, fdRead,fdWrite, fdTruncate, fdSeek
For an example, see fdRead.