nbd_get_structured_replies_negotiated3

Usage

 #include <libnbd.h>
 int nbd_get_structured_replies_negotiated (
       struct nbd_handle *h
     );

Overview

After connecting you may call this to find out if the connection is using structured replies. Note that this setting is sticky; this can return true even after a second nbd_opt_structured_reply(3) returns false because the server detected a duplicate request.

Note that if the connection negotiates extended headers, this function returns true (as extended headers imply structured replies) even if no explicit request for structured replies was attempted.

Return value

This call returns a boolean value.

Errors

On error -1 is returned.

Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

The following parameters must not be NULL: "h". For more information see "Non-NULL parameters" in libnbd(3).

Handle state

nbd_get_structured_replies_negotiated can be called when the handle is in the following states:

 ┌─────────────────────────────────────┬─────────────────────────┐
 │ Handle created, before connecting   │ ❌ error                │
 │ Connecting                          │ ❌ error                │
 │ Connecting & handshaking (opt_mode) │ ✅ allowed              │
 │ Connected to the server             │ ✅ allowed              │
 │ Connection shut down                │ ✅ allowed              │
 │ Handle dead                         │ ❌ error                │
 └─────────────────────────────────────┴─────────────────────────┘

Version

This function first appeared in libnbd 1.2.

If you need to test if this function is available at compile time check if the following macro is defined:

 #define LIBNBD_HAVE_NBD_GET_STRUCTURED_REPLIES_NEGOTIATED 1