c - Redirecting Output -

When I do not understand anything, then I was playing with redirection.

I have a basic multi-client server program that connects a user or writes a message for standard output when disconnecting.

If I run 2 clients in other terminals and shut down, the output will be something like this:

  Waiting for connection .... A user   
 If I redirect the output via a file  
 , a user connected to a user connected to a user disconnected   
 ./ Server & gt; logfile.txt   
 When I open the logfile, I see something like this:  
  Waiting for connection. ... A user connected to a user is waiting for connection disconnected .... Disconnect connected to a user   
 My question is: How do I get the same output Can i do   
 
 
 My suspicion is that there is such a code in your server program:  
  printf "is waiting for connection ... \ n"); While ((handle = new_connection ())! = 0) {if ((pid = fork ()) <0 fprintf (stderr, "..."); else if (pid == 0) {printf ("Connect a user \ n"); manage_connection (handle); Printf ("One user disconnected \ n"); Exit (0); }}   
 When you go with the output to the terminal, the output buffer buffer occurs, so the  waiting  message is displayed immediately.  
 When the output is out in a file, the output is completely buffer; The buffer fills, or the obvious  fflush ()  occurs, or a  fclose () , or the process normally exits, the file is not sent until This means that there is a  waiting  message in its buffer in the hair process, and a copy of the message will be printed for each child's process.  
 The only way to fix this is to modify the server program. You can use  fflush ()  after printing the 'Wait' message (and before the loop), or you can explicitly set output buffering on  _IOLBF  Are there.