Added : ability to manually select the dictionary ID of a newly created dictionary

programs/zstd.1

@@ -18,11 +18,11 @@
 .PP
 .B unzstd
 is equivalent to
-.BR "zstd \-d" 
+.BR "zstd \-d"
 .br
 .B zstdcat
 is equivalent to
-.BR "zstd \-dc" 
+.BR "zstd \-dc"
 .br
 
 .SH DESCRIPTION
@@ -90,7 +90,15 @@ Typical gains range from ~10% (at 64KB) to x5 better (at <1KB).
  dictionary saved into `file` (default: dictionary)
 .TP
 .B \--maxdict #
- limit dictionary to specified size (default : 112640) 
+ limit dictionary to specified size (default : 112640)
+.TP
+.B \--dictID #
+ A dictionary ID is a locally unique ID that a decoder can use to verify it is using the right dictionary.
+ By default, zstd will create a 4-bytes random number ID.
+ It's possible to give a precise number instead.
+ Short numbers have an advantage : an ID < 256 will only need 1 byte in the compressed frame header,
+ and an ID < 65536 will only need 2 bytes. This compares favorably to 4 bytes default.
+ However, it's up to the dictionary manager to not assign twice the same ID to 2 different dictionaries.
 .TP
 .B \-s#
  dictionary selectivity level (default: 9)