Document EMSGSIZE return from recvmsg due to insufficient free files

when transfering rights (file descriptors.)

1 files changed, 10 insertions, 1 deletions

diff --git a/lib/libc/sys/recv.2 b/lib/libc/sys/recv.2
index 1131824..51d8d61 100644
--- a/lib/libc/sys/recv.2
+++ b/lib/libc/sys/recv.2
@@ -207,7 +207,9 @@ struct cmsghdr {
 .Ed
 As an example, one could use this to learn of changes in the data-stream
 in XNS/SPP, or in ISO, to obtain user-connection-request data by requesting
-a recvmsg with no data buffer provided immediately after an
+a
+.Fn recvmsg
+with no data buffer provided immediately after an
 .Fn accept
 system call.
 .Pp
@@ -287,6 +289,13 @@ and
 The argument
 .Fa s
 does not refer to a socket.
+.It Bq Er EMSGSIZE
+.Fn recvmsg
+was used to receive rights (file descriptors) that were in flight on the
+connection.  However, the receiving program did not have enough free file
+descriptor slots to accept the them.  In this case the descriptors are
+closed, any pending data can be returned by another call to
+.Fn recvmsg .
 .It Bq Er EAGAIN
 The socket is marked non-blocking, and the receive operation
 would block, or