diff --git a/src/lib/plugin.c b/src/lib/plugin.c
index 4005bb204..062e266b5 100644
--- a/src/lib/plugin.c
+++ b/src/lib/plugin.c
@@ -100,6 +100,10 @@ cinelerra_plugin_name_cmp (const void* a, const void* b)
   return strcmp (((struct cinelerra_plugin*) a)->name, ((struct cinelerra_plugin*) b)->name);
 }
 
+/**
+ * Initialize the plugin system.
+ * always succeeds or aborts
+ */
 void
 cinelerra_init_plugin (void)
 {
@@ -149,6 +153,16 @@ cinelerra_plugin_lookup (struct cinelerra_plugin* self, const char* path)
   return -1; /* plugin not found */
 }
 
+
+/**
+ * Make an interface available.
+ * To use an interface provided by a plugin it must be opened first. It is allowed to open an interface more than once.
+ * Each open must be paired with a close.
+ * @param plugin name of the plugin to use.
+ * @param name name of the interface to open.
+ * @param min_revision the size of the interface structure is used as measure of a minimal required revision (new functions are appended at the end)
+ * @return handle to the interface or NULL in case of a error. The application shall cast this handle to the actual interface type.
+ */
 struct cinelerra_interface*
 cinelerra_interface_open (const char* name, const char* interface, size_t min_revision)
 {
@@ -277,6 +291,11 @@ cinelerra_interface_open (const char* name, const char* interface, size_t min_re
   return NULL;
 }
 
+/**
+ * Close an interface. Does not free associated resources
+ * Calling this function with self==NULL is legal. Every interface handle must be closed only once.
+ * @param self interface to be closed
+ */
 void
 cinelerra_interface_close (void* ptr)
 {
diff --git a/src/lib/plugin.h b/src/lib/plugin.h
index b787870d2..a710c8285 100644
--- a/src/lib/plugin.h
+++ b/src/lib/plugin.h
@@ -90,32 +90,14 @@ struct cinelerra_interface
   int (*close)(void);
 };
 
-/**
- * Initialize the plugin system.
- * always succeeds or aborts
- */
 void
 cinelerra_init_plugin (void);
 
 
-/**
- * Make an interface available.
- * To use an interface provided by a plugin it must be opened first. It is allowed to open an interface more than once.
- * Each open must be paired with a close.
- * @param plugin name of the plugin to use.
- * @param name name of the interface to open.
- * @param min_revision the size of the interface structure is used as measure of a minimal required revision (new functions are appended at the end)
- * @return handle to the interface or NULL in case of a error. The application shall cast this handle to the actual interface type.
- */
 struct cinelerra_interface*
 cinelerra_interface_open (const char* plugin, const char* name, size_t min_revision);
 
 
-/**
- * Close an interface. Does not free associated resources
- * Calling this function with self==NULL is legal. Every interface handle must be closed only once.
- * @param self interface to be closed
- */
 void
 cinelerra_interface_close (void* self);