`curl_ws_send()` leaves `*sent` unchanged on one blocking raw-send path

[m1-llie]

I did this

I traced the blocking raw-send path in lib/ws.c and found that ws_send_raw_blocking() has no pnwritten output parameter, so the surrounding ws_send_raw() path can succeed without updating the caller's *sent value. In practice, callers using curl_ws_send() from inside a callback in raw mode can observe *sent == 0 even though the bytes were written.
It looks like an API-contract bug in the current lib/ws.c logic.

The call path is:

curl_ws_send()       — zeroes *pnsent before dispatching
  -> ws_send_raw()
     -> ws_send_raw_blocking()  — succeeds but never writes to pnwritten

Confirmed in current HEAD (lib/ws.c):

• curl_ws_send() initialises *pnsent = 0 and delegates to ws_send_raw()
• In the blocking callback path, ws_send_raw() calls ws_send_raw_blocking()
• ws_send_raw_blocking() has no pnwritten output parameter and does not write back through the caller's pointer
• On return, *pnsent remains 0 even though bytes were sent

I expected the following

On success, the blocking raw-send path should report the number of bytes written to the caller just like the non-blocking path does.

curl/libcurl version

curl 8.20.0-DEV (70281e3) in lib/ws.c

operating system

Linux x86_64

[icing]

Thanks for the report. I propose to fix this via #21373.