unix_seqpacket_recvmsg() calls unix_dgram_recvmsg() which handles MSG_TRUNC. This has been the case since the handling was added in 9f6f9af7694ede6314bed281eec74d588ba9474f; see net/unix/af_unix.c: static int unix_seqpacket_recvmsg([...]) { [...] return unix_dgram_recvmsg(iocb, sock, msg, size, flags); } The sequential-packet socket type seems to have been left out from the description by an oversight. Signed-off-by: Vladislav Ivanishin <vlad@xxxxxxxxx> --- Hi Alex, On Sun, Dec 11 2022, Alejandro Colomar <alx.manpages@xxxxxxxxx> wrote: > Hi Vladislav, > > On 11/27/22 11:38, Vladislav Ivanishin wrote: >> unix_seqpacket_recvmsg() calls unix_dgram_recvmsg() which handles >> MSG_TRUNC. This has been the case since the support for this flag was >> implemented in the latter; the sequential-packet socket type seems to >> have been left out from the description by an oversight. >> Signed-off-by: Vladislav Ivanishin<vlad@xxxxxxxxx> > > Could you please point to the relevant kernel commits, or quote the relevant > lines of code, in the commit message? > > Thanks, > > Alex Sure, here's an updated version. Vlad man2/recv.2 | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/man2/recv.2 b/man2/recv.2 index 5298a2745..81cd1957c 100644 --- a/man2/recv.2 +++ b/man2/recv.2 @@ -226,7 +226,8 @@ subsequent receive call will return the same data. For raw .RB ( AF_PACKET ), Internet datagram (since Linux 2.4.27/2.6.8), -netlink (since Linux 2.6.22), and UNIX datagram +netlink (since Linux 2.6.22), +and UNIX datagram as well as sequenced-packet .\" commit 9f6f9af7694ede6314bed281eec74d588ba9474f (since Linux 3.4) sockets: return the real length of the packet or datagram, -- 2.39.1