diff --git a/darwin/opentype.m b/darwin/opentype.m
new file mode 100644
index 00000000..4273b80f
--- /dev/null
+++ b/darwin/opentype.m
@@ -0,0 +1,52 @@
+// 11 may 2017
+#include "uipriv_windows.hpp"
+
+struct uiOpenTypeFeatures {
+	xxxx;
+};
+
+uiOpenTypeFeatures *uiNewOpenTypeFeatures(void)
+{
+	uiOpenTypeFeatures *otf;
+
+	otf = uiNew(uiOpenTypeFeatures);
+	xxxx;
+	return otf;
+}
+
+void uiFreeOpenTypeFeatures(uiOpenTypeFeatures *otf)
+{
+	xxxxxx;
+	uiFree(otf);
+}
+
+uiOpenTypeFeatures *uiOpenTypeFeaturesClone(uiOpenTypeFeatures *otf)
+{
+	uiOpenTypeFeatures *out;
+
+	out = uiNew(uiOpenTypeFeatures);
+	xxxxxx;
+	return out;
+}
+
+void uiOpenTypeFeaturesAdd(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t value)
+{
+}
+
+void uiOpenTypeFeaturesRemove(uiOpenTypeFeatures *otf, char a, char b, char c, char d)
+{
+}
+
+int uiOpenTypeFeaturesGet(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t *value)
+{
+}
+
+void uiOpenTypeFeaturesForEach(uiOpenTypeFeatures *otf, uiOpenTypeFeaturesForEachFunc f, void *data)
+{
+}
+
+int uiOpenTypeFeaturesEqual(uiOpenTypeFeatures *a, uiOpenTypeFeatures *b)
+{
+}
+
+// TODO put the internal function to produce a backend object from one here
diff --git a/ui_attrstr.h b/ui_attrstr.h
index 0077b6ee..f7c03b03 100644
--- a/ui_attrstr.h
+++ b/ui_attrstr.h
@@ -220,13 +220,19 @@ _UI_ENUM(uiAttributeCapForm) {
 
 // TODO rename?
 typedef struct uiOpenTypeFeatures uiOpenTypeFeatures;
+// TODO pass the feature set?
+typedef int (*uiOpenTypeFeaturesForEachFunc)(char a, char b, char c, char d, uint32_t value, void *data);
 // TODO detailed constructor?
 _UI_EXTERN uiOpenTypeFeatures *uiNewOpenTypeFeatures(void);
 _UI_EXTERN void uiFreeOpenTypeFeatures(uiOpenTypeFeatures *otf);
+// TODO put above Free?
+// TODO Copy instead of Clone?
 _UI_EXTERN uiOpenTypeFeatures *uiOpenTypeFeaturesClone(uiOpenTypeFeatures *otf);
 _UI_EXTERN void uiOpenTypeFeaturesAdd(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t value);
-// TODO remove, query, enumerate
-// TODO make the compare function public?
+_UI_EXTERN void uiOpenTypeFeaturesRemove(uiOpenTypeFeatures *otf, char a, char b, char c, char d);
+_UI_EXTERN int uiOpenTypeFeaturesGet(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t *value);
+_UI_EXTERN void uiOpenTypeFeaturesForEach(uiOpenTypeFeatures *otf, uiOpenTypeFeaturesForEachFunc f, void *data);
+_UI_EXTERN int uiOpenTypeFeaturesEqual(uiOpenTypeFeatures *a, uiOpenTypeFeatures *b);
 
 typedef struct uiAttributeSpec uiAttributeSpec;
 
@@ -240,6 +246,7 @@ struct uiAttributeSpec {
 	double A;
 };
 
+// TODO name the foreach return values
 typedef int (*uiAttributedStringForEachAttributeFunc)(uiAttributedString *s, uiAttributeSpec *spec, size_t start, size_t end, void *data);
 
 // @role uiAttributedString constructor
diff --git a/unix/opentype.c b/unix/opentype.c
new file mode 100644
index 00000000..4273b80f
--- /dev/null
+++ b/unix/opentype.c
@@ -0,0 +1,52 @@
+// 11 may 2017
+#include "uipriv_windows.hpp"
+
+struct uiOpenTypeFeatures {
+	xxxx;
+};
+
+uiOpenTypeFeatures *uiNewOpenTypeFeatures(void)
+{
+	uiOpenTypeFeatures *otf;
+
+	otf = uiNew(uiOpenTypeFeatures);
+	xxxx;
+	return otf;
+}
+
+void uiFreeOpenTypeFeatures(uiOpenTypeFeatures *otf)
+{
+	xxxxxx;
+	uiFree(otf);
+}
+
+uiOpenTypeFeatures *uiOpenTypeFeaturesClone(uiOpenTypeFeatures *otf)
+{
+	uiOpenTypeFeatures *out;
+
+	out = uiNew(uiOpenTypeFeatures);
+	xxxxxx;
+	return out;
+}
+
+void uiOpenTypeFeaturesAdd(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t value)
+{
+}
+
+void uiOpenTypeFeaturesRemove(uiOpenTypeFeatures *otf, char a, char b, char c, char d)
+{
+}
+
+int uiOpenTypeFeaturesGet(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t *value)
+{
+}
+
+void uiOpenTypeFeaturesForEach(uiOpenTypeFeatures *otf, uiOpenTypeFeaturesForEachFunc f, void *data)
+{
+}
+
+int uiOpenTypeFeaturesEqual(uiOpenTypeFeatures *a, uiOpenTypeFeatures *b)
+{
+}
+
+// TODO put the internal function to produce a backend object from one here
diff --git a/windows/opentype.cpp b/windows/opentype.cpp
new file mode 100644
index 00000000..4273b80f
--- /dev/null
+++ b/windows/opentype.cpp
@@ -0,0 +1,52 @@
+// 11 may 2017
+#include "uipriv_windows.hpp"
+
+struct uiOpenTypeFeatures {
+	xxxx;
+};
+
+uiOpenTypeFeatures *uiNewOpenTypeFeatures(void)
+{
+	uiOpenTypeFeatures *otf;
+
+	otf = uiNew(uiOpenTypeFeatures);
+	xxxx;
+	return otf;
+}
+
+void uiFreeOpenTypeFeatures(uiOpenTypeFeatures *otf)
+{
+	xxxxxx;
+	uiFree(otf);
+}
+
+uiOpenTypeFeatures *uiOpenTypeFeaturesClone(uiOpenTypeFeatures *otf)
+{
+	uiOpenTypeFeatures *out;
+
+	out = uiNew(uiOpenTypeFeatures);
+	xxxxxx;
+	return out;
+}
+
+void uiOpenTypeFeaturesAdd(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t value)
+{
+}
+
+void uiOpenTypeFeaturesRemove(uiOpenTypeFeatures *otf, char a, char b, char c, char d)
+{
+}
+
+int uiOpenTypeFeaturesGet(uiOpenTypeFeatures *otf, char a, char b, char c, char d, uint32_t *value)
+{
+}
+
+void uiOpenTypeFeaturesForEach(uiOpenTypeFeatures *otf, uiOpenTypeFeaturesForEachFunc f, void *data)
+{
+}
+
+int uiOpenTypeFeaturesEqual(uiOpenTypeFeatures *a, uiOpenTypeFeatures *b)
+{
+}
+
+// TODO put the internal function to produce a backend object from one here