Wireshark-dev: [Wireshark-dev] Re: warning C4702: unreachable code

From: Michael Mann <mmann78@xxxxxxxxxxxx>
Date: Tue, 3 Feb 2026 16:40:59 +0000 (UTC)
I looked at the first example (packet-blip.c) and it's using a macro to throw an exception, then returns NULL (the "return" is considered the "unreachable code")
Not sure if the macro is build configuration dependent (Debug vs Release), but I'm fine with the style of code used there and it's probably why we don't use the additional Visual Studio flags you enabled.



On Tuesday, February 3, 2026 at 06:14:49 AM EST, Tamás Regős <regost@xxxxxxxxx> wrote:


Hi Dev Team,

While I was trying to run some of the pipeline logic locally on my Windows machine related to my earlier emails and new MRs (!23460, !23461), I recompiled WS with some additional Visual Studio flags for clang checks and I can see a lots of "warning C4702: unreachable code".

Should these be addressed and fixed via MRs?

wireshark\epan\dissectors\packet-blip.c(323,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-cbor.c(390,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-cbor.c(501,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-catapult-dct2000.c(3402,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-cip.c(6610,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-dof.c(5814,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-exported_pdu.c(215,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-fpp.c(307,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-h223.c(1157,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-h223.c(1169,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-h223.c(1095,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-http.c(996,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ieee80211.c(39522,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(1296,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(1094,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(1886,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(1925,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(1951,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(1972,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(2019,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(2057,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(2080,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(2116,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(2137,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ipsec.c(2160,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-iso15765.c(1013,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-iuup.c(721,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-megaco.c(293,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-mtp3.c(250,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-mtp3.c(272,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-mtp3.c(277,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-mswsp.c(4064,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-mswsp.c(4953,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2064,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2150,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2226,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2254,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2450,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2095,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2176,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(1529,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2403,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2428,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-netlink-netfilter.c(2522,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-null.c(312,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-obd-ii.c(1500,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-obd-ii.c(1459,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-obd-ii.c(1502,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-oer.c(520,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-oer.c(646,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-oer.c(652,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-oer.c(695,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(375,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(392,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(431,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(462,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(474,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(534,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(1213,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(1272,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(2109,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-per.c(917,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ppp.c(1829,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-pw-atm.c(281,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-pw-atm.c(309,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-pw-atm.c(285,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-pw-atm.c(314,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-pw-atm.c(354,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-quic.c(3687,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-reload.c(1880,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-reload.c(1868,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-rsvp.c(2651,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-rsvp.c(2709,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-rtps.c(12951,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-sll.c(209,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-sll.c(235,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-snort.c(1340,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-snort.c(1341,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-snort.c(1353,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-snort.c(1358,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-snort.c(1363,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-spice.c(1526,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ssh.c(2028,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ssh.c(2090,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-wcp.c(628,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-xcp.c(1780,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-xcp.c(2755,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-xcp.c(3022,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-xcp.c(1864,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-acse.c(1649,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-camel.c(3327,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-charging_ase.c(511,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-h248.c(1044,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-spnego.c(328,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-dcerpc-nt.c(1026,1): warning C4702: unreachable code
wireshark\epan\dissectors\packet-ncp2222.inc(7023,1): warning C4702: unreachable code

Regards,
Tamas
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