+.TP 5
+.na
+.hy 0
+\fBslk_attroff\fP, \fBslk_attron\fP, \fBslk_clear\fP, \fBslk_noutrefresh\fP, \fBslk_refresh\fP, \fBslk_touch\fP
+.ad
+.hy
+return an error
+if the terminal or the softkeys were not initialized.
+.TP 5
+\fBslk_attrset\fP
+returns an error
+if the terminal or the softkeys were not initialized.
+.TP 5
+\fBslk_attr_set\fP
+returns an error
+if the terminal or the softkeys were not initialized, or
+the color pair is outside the range 0..COLOR_PAIRS\-1,
+or opts is not null.
+.TP 5
+\fBslk_color\fP
+returns an error
+if the terminal or the softkeys were not initialized, or
+the color pair is outside the range 0..COLOR_PAIRS\-1.
+.TP 5
+\fBslk_init\fR
+returns an error
+if the format parameter is outside the range 0..3.
+.TP 5
+\fBslk_label\fR
+returns \fBNULL\fR on error.
+.TP 5
+\fBslk_set\fP
+returns an error
+if the terminal or the softkeys were not initialized, or
+the \fIlabnum\fP parameter is outside the range of label counts, or
+if the format parameter is outside the range 0..2, or if
+memory for the labels cannot be allocated.
+.RE