[PATCH 2/3] recv_cmd: do not undef recvmsg buffer arg on errors

[Eric Wong <e@80x24.org>]

It's a waste of ops and cycles, and inconsistent with perl
sysread() behavior which doesn't touch the supplied buffer on
errors.
---
 lib/PublicInbox/CmdIPC4.pm | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/CmdIPC4.pm b/lib/PublicInbox/CmdIPC4.pm
index c3a7f56e..76938b6d 100644
--- a/lib/PublicInbox/CmdIPC4.pm
+++ b/lib/PublicInbox/CmdIPC4.pm
@@ -1,4 +1,4 @@
-# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # callers should use PublicInbox::CmdIPC4->can('send_cmd4') (or recv_cmd4)
@@ -32,7 +32,7 @@ no warnings 'once';
 *recv_cmd4 = sub ($$$) {
 	my ($s, undef, $len) = @_; # $_[1] = destination buffer
 	my $mh = Socket::MsgHdr->new(buflen => $len, controllen => 256);
-	my $r = Socket::MsgHdr::recvmsg($s, $mh, 0) // return ($_[1] = undef);
+	my $r = Socket::MsgHdr::recvmsg($s, $mh, 0) // return (undef);
 	$_[1] = $mh->buf;
 	return () if $r == 0;
 	my (undef, undef, $data) = $mh->cmsghdr;