From 571df2c64a3c1af1fe011303ec08e391e887ecbc Mon Sep 17 00:00:00 2001
From: Felix Johnson <fjohnson@felix-johnson.com>
Date: Wed, 12 Feb 2025 22:40:59 -0500
Subject: [PATCH] recv.2: Explain how recv functions can return 0

Clarify the RETURN VALUES section with improved structure,
the condition of the return value 0, and the setting of errno.

PR:			174581
Reviewed by:		jhb, ziaee
Approved by:		mhorne (mentor)
Differential Revision:	https://reviews.freebsd.org/D48955
---
 lib/libsys/recv.2 | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/libsys/recv.2 b/lib/libsys/recv.2
index 08df62af3d1..9dc1f3cc84c 100644
--- a/lib/libsys/recv.2
+++ b/lib/libsys/recv.2
@@ -316,12 +316,19 @@ On data reception the
 .Fa msg_len
 field is updated to the length of the received message.
 .Sh RETURN VALUES
-These calls except
-.Fn recvmmsg
+On successful completion,
+.Fn recv ,
+.Fn recvfrom ,
+and
+.Fn recvmsg
 return the number of bytes received.
 .Fn recvmmsg
 returns the number of messages received.
-A value of -1 is returned if an error occurred.
+If no messages are available to be received and the peer has
+performed an orderly shutdown, 0 is returned.
+Otherwise, -1 is returned and
+.Va errno
+is set to indicate the error.
 .Sh ERRORS
 The calls fail if:
 .Bl -tag -width Er