sprintf ignores field width

[nick.g]

I'm using sprintf as a clean way of copying four bytes of data from one array into another and placing a null terminator after them:

sprintf( dest, "%4s", cValueArray );

However, it seems to be not just copying four bytes from cValueArray, but instead copying up to where it finds a null terminator.  I found one post about a similar problem, that didn't seem to be answered: http://forums.ni.com/ni/board/message?board.id=180&message.id=11632&query.id=440390#M11632

Thanks in advance for any help.
-Nick

[RobertoBozzolo]

Well, according to K&R the correct attribute to use is precision, not minimum field width. That is:
sprintf (dest, "%.4s", cValueArray );    (Please note the dot )

copies exactly 4 bytes to destination string adding a nul terminator at the end.

[nick.g]

Aha - my mistake.  Thanks very much!

It's worth noting that the field width, as I originally uses it, specifies the minimum amount of space to be taken up in the destination string by that conversion specifier (using spaces to pad on the left if the result of the conversion takes up fewer characters than specified by the given field width).