Clarified lv2.h header for HostFeatures parameter, associated changes to SLV2.

git-svn-id: http://svn.drobilla.net/lad/slv2@195 a436a847-0d15-0410-975c-d299462d15a1

2 files changed, 8 insertions, 2 deletions

diff --git a/slv2/lv2.h b/slv2/lv2.h
index b3d97bf..7e3b14e 100644
--- a/slv2/lv2.h
+++ b/slv2/lv2.h
@@ -146,13 +146,15 @@ typedef struct _LV2_Descriptor {
    * found. This function must return NULL if instantiation fails.
    *
    * BundlePath is a string of the path to the plugin's .lv2 bundle
-   * directory, it MUST not include the trailing /.
+   * directory, it MUST NOT include the trailing /.
    *
    * HostFeatures is a NULL terminated array of the URIs of the LV2
    * features that the host supports. Plugins may refuse to instantiate
    * if required features are not found here (however hosts SHOULD NOT use
    * this as a discovery mechanism, instead reading the data file before
-   * attempting to instantiate the plugin).
+   * attempting to instantiate the plugin).  This array must always exist;
+   * if a host has no features, it MUST pass a single element array
+   * containing NULL (to simplify plugins).
    *
    * Note that instance initialisation should generally occur in
    * activate() rather than here.  If a host calls instantiate, it MUST
diff --git a/slv2/plugininstance.h b/slv2/plugininstance.h
index aba3f95..553bb74 100644
--- a/slv2/plugininstance.h
+++ b/slv2/plugininstance.h
@@ -54,6 +54,10 @@ typedef const struct _Instance SLV2Instance;
  * \a plugin is not modified or directly referenced by the returned object
  * (instances store only a copy of the plugin's URI).
  * 
+ * \a host_features NULL-terminated array of features the host supports.
+ * NULL may be passed if the host supports no additional features (unlike
+ * the LV2 specification - SLV2 takes care of it).
+ *
  * \return NULL if instantiation failed.
  */
 SLV2Instance*