doc: explain isl_*_is_subset

Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>

diff --git a/doc/user.pod b/doc/user.pod
index 7869890..793b5bd 100644 (file)
--- a/doc/user.pod
+++ b/doc/user.pod
@@ -1813,6 +1813,9 @@ Check whether the domain of the (basic) relation is a wrapped relation.
                __isl_keep isl_union_map *umap1,
                __isl_keep isl_union_map *umap2);
 
+Check whether the first argument is a (strict) subset of the
+second argument.
+
 =back
 
 =head2 Unary Operations