+It added \fB\%slk_color\fP.
+.PP
+Although \fB\%slk_start\fP is declared in the \fIcurses\fP header file,
+it was not documented by SVr4 other than its presence in a list
+of libtermlib.so.1 symbols.
+Reading the source code (i.e., Illumos):
+.bP
+\fB\%slk_start\fP has two parameters:
+.RS
+.bP
+\fIng\fP (number of groups) and
+.bP
+\fIgp\fP (group pointer).
+.RE
+.bP
+Soft-key groups are an array of \fIng\fP integers.
+.bP
+In SVr4, \fB\%slk_init\fP calls \fB\%slk_start\fP passing a null for \fIgp\fP.
+For this case, \fB\%slk_start\fP uses the number of groups \fIng\fP
+(3 for the 3-2-3 layout, 2 for the 4-4 layout) which \fB\%slk_init\fP provided.
+.IP
+If \fIng\fP is neither 2 or 3,
+\fB\%slk_start\fP checks the terminfo \fBfln\fP (label_format) capability,
+interpreting that as a comma-separated list of numbers,
+e.g., \*(``3,2,3\*('' for the 3-2-3 layout.
+.IP
+Finally, if there is no \fBfln\fP capability,
+\fB\%slk_start\fP returns \fBERR\fP.
+.bP
+If \fB\%slk_start\fP is given a non-null \fIgp\fP,
+it copies the \fIng\fP elements of the group of soft-keys, up to 16.
+.IP
+If there are more than 16 elements, \fB\%slk_start\fP returns an error.
+.bP
+The format codes \fB2\fP and \fB3\fP for \fB\%slk_init\fP
+were added by \fIncurses\fP in 1996.
+PDCurses 2.4 added this feature in 2001.