The %m$nd format has to do with the XPG4 standard, as defined by The Open
Group (formerly X/Open and OSF, I believe).  It allows the rearrangement of
the arguments with regard to localization.

An example of this usage would be localizing the display of a date.  To
show a date in American format, you could use something like this:

 sprintf( c_datestring, "%2$02d/%1$02d/%3$04d",
	(int)tmdate.tm_mday, (int)tmdate.tm_mon+1,
	(int)tmdate.tm_year+1900 );

But the European format reverses the month and day, like this:

 sprintf( c_datestring, "%1$02d/%2$02d/%3$04d",
	(int)tmdate.tm_mday, (int)tmdate.tm_mon+1,
	(int)tmdate.tm_year+1900 );

The value of this becomes apparent when the format string itself is
read from a message catalog.

You can find details on www.opengroup.org and searching for sprintf in
"The Single Unix Specification" (which you must hunt for, and register
to read for free).

--- Forwarded mail from wulf@ping.net.au

does anyone know the following construct? It was found in anteater
which segfaults at that point.

[...]
 sprintf( c_datestring, "year %1$02d, day %2$02d, month %3$04d",
	(int)tmdate.tm_mday, (int)tmdate.tm_mon+1,
	(int)tmdate.tm_year+1900 );
  string newdate = c_datestring;
  return newdate;

I've expanded the format string which is constructed earlier
in the code. I've never seen the use of a "%1$02d" format string nor have I
found any references in books and manuals. When changed to 
"%02d" the program runs fine and displays the correct date format.

Is there a new stdlib with extentions of the current format string? I am 
using egcs-1.1.1 and standard libraries as shipped with NetBSD-1.4.1.

--- End of forwarded message from wulf@ping.net.au