[Libguestfs] [PATCH libnbd v2 4/5] docs: callbacks: Document that user_data, valid_flag only used by the C API.

Thanks: Eric Blake. --- docs/libnbd.pod | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/docs/libnbd.pod b/docs/libnbd.pod index 0ce4d32..6c8d962 100644 --- a/docs/libnbd.pod +++ b/docs/libnbd.pod @@ -487,7 +487,9 @@ C<nbd_set_debug_callback>, C<nbd_pread_callback>). Libnbd can call these functions while processing. Callbacks have an opaque C<void *user_data> pointer. This is passed -as the second parameter to the callback. +as the second parameter to the callback. The opaque pointer is only +used from the C API, since in other languages you can use closures to +achieve the same outcome. =head2 Callback lifetimes @@ -539,6 +541,9 @@ write this: // Rest of callback as normal. } +The valid flag is only present in the C API. It is not needed when +using garbage-collected programming languages. + =head2 Callbacks and locking The callbacks are invoked at a point where the libnbd lock is held; as -- 2.22.0