Nathan Weeks raised an issue with Aharon Robbins, pointing out that B…

…WK awk

accepts an empty string or no parameters to denote flush-all-output.  Aharon
cc'd me for response.  I'd not known this, but discovered mawk does that too.
However mawk didn't propagate an inadvertant I/O error from a real fflush up.
It did an error exit.  For consistency with gawk/BWK, I got rid of the exit
and propagated the error up.

CHANGES

@@ -1,8 +1,12 @@
--- $MawkId: CHANGES,v 1.162 2012/11/28 20:44:12 tom Exp $
+-- $MawkId: CHANGES,v 1.163 2012/11/29 00:55:33 tom Exp $
 
 Changes by Thomas E Dickey <dickey@invisible-island.net>
 
 20121129
+	+ change behavior if internal fflush call fails: rather than exiting
+	  with an error, propagate the return value to the script as -1, for
+	  consistency with gawk and BWK (discussion with Aharon Robbins and
+	  Nathan Weeks).
 	+ add special case for forward reference to a function using an array
 	  parameter, updating the function's parameter type so that the array
 	  is passed properly.

files.h

@@ -1,6 +1,6 @@
 /********************************************
 files.h
-copyright 2009,2010, Thomas E. Dickey
+copyright 2009-2010,2012 Thomas E. Dickey
 copyright 1991-1994,1996, Michael D. Brennan
 
 This is a source file for mawk, an implementation of
@@ -11,7 +11,7 @@ the GNU General Public License, version 2, 1991.
 ********************************************/
 
 /*
- * $MawkId: files.h,v 1.11 2010/12/10 17:00:00 tom Exp $
+ * $MawkId: files.h,v 1.12 2012/11/29 00:56:19 tom Exp $
  * @Log: files.h,v @
  * Revision 1.3  1996/01/14  17:14:11  mike
  * flush_all_output()
@@ -50,7 +50,7 @@ extern const char *shell;	/* for pipes and system() */
 extern PTR file_find(STRING *, int);
 extern int file_close(STRING *);
 extern int file_flush(STRING *);
-extern void flush_all_output(void);
+extern int flush_all_output(void);
 extern PTR get_pipe(char *, int, int *);
 extern int wait_for(int);
 extern void close_out_pipes(void);