From 28ee21cecbd2eb5d347c65bc9c87c8100dd33774 Mon Sep 17 00:00:00 2001 From: David Robillard Date: Thu, 19 Oct 2006 00:06:50 +0000 Subject: Added extension_data hook to LV2_Descriptor git-svn-id: http://svn.drobilla.net/lad/slv2@189 a436a847-0d15-0410-975c-d299462d15a1 --- slv2/lv2.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'slv2/lv2.h') diff --git a/slv2/lv2.h b/slv2/lv2.h index e38e2ac..b3d97bf 100644 --- a/slv2/lv2.h +++ b/slv2/lv2.h @@ -260,6 +260,31 @@ typedef struct _LV2_Descriptor { * Hosts MUST NOT call cleanup() unless instantiate() was previously * called. */ void (*cleanup)(LV2_Handle Instance); + + /** Function pointer that can be used to return additional instance data for + * a plugin defined by some extenion (e.g. a struct containing additional + * function pointers). + * + * The actual type and meaning of the returned object MUST be specified + * precisely by the extension if it defines any extra data. If a particular + * extension does not define extra instance data, this function MUST return + * NULL for that extension's URI. If a plugin does not support any + * extensions that define extra instance data, this function pointer may be + * set to NULL rather than providing an empty function. + * + * The only parameter is the URI of the extension. The plugin MUST return + * NULL if it does not support the extension, but hosts SHOULD NOT use this + * as a discovery method (e.g. hosts should only call this function for + * extensions known to be supported by the plugin from the data file). + * + * NOTE: It is highly recommended that this function returns a struct, and + * NOT a direct function pointer. Standard C++ (for real reasons) does not + * allow type casts from void* to a function pointer type. To provide + * additional functions a struct should be returned containing the extra + * function pointers (which is valid standard C++, and a much better idea + * for extensibility anyway). + */ + void* (*extension_data)(const char * URI); } LV2_Descriptor; -- cgit v1.2.1