diff --git a/libtransmission/.clang-tidy b/libtransmission/.clang-tidy
index eba144a5d..b9f5e4b70 100644
--- a/libtransmission/.clang-tidy
+++ b/libtransmission/.clang-tidy
@@ -5,17 +5,9 @@ Checks: >
   -bugprone-branch-clone,
   -bugprone-easily-swappable-parameters,
   -bugprone-implicit-widening-of-multiplication-result,
-  -bugprone-incorrect-roundings,
   -bugprone-narrowing-conversions,
-  -bugprone-not-null-terminated-result,
-  -bugprone-reserved-identifier,
-  -bugprone-signed-char-misuse,
-  -bugprone-sizeof-expression,
-  -bugprone-suspicious-include,
   cert-*,
-  -cert-dcl37-c,
   -cert-dcl50-cpp,
-  -cert-dcl51-cpp,
   -cert-err33-c,
   -cert-err34-c,
   -cert-err58-cpp,
@@ -26,23 +18,19 @@ Checks: >
   clang-analyzer-valist.*,
   cppcoreguidelines-init-variables,
   cppcoreguidelines-prefer-member-initializer,
+  cppcoreguidelines-slicing,
   cppcoreguidelines-virtual-class-destructor,
   misc-*,
-  -misc-misplaced-const,
   -misc-no-recursion,
   -misc-non-private-member-variables-in-classes,
   modernize-*,
   -modernize-avoid-c-arrays,
-  -modernize-raw-string-literal,
   -modernize-use-trailing-return-type,
   performance-*,
   readability-*,
   -readability-function-cognitive-complexity,
   -readability-identifier-length,
-  -readability-implicit-bool-conversion,
   -readability-inconsistent-declaration-parameter-name,
   -readability-magic-numbers,
-  -readability-named-parameter,
   -readability-qualified-auto,
   -readability-redundant-access-specifiers,
-  -readability-static-accessed-through-instance,
diff --git a/libtransmission/announcer-http.cc b/libtransmission/announcer-http.cc
index b4b9c89b6..1982ede45 100644
--- a/libtransmission/announcer-http.cc
+++ b/libtransmission/announcer-http.cc
@@ -71,7 +71,7 @@ static std::string announce_url_new(tr_session const* session, tr_announce_reque
         "&compact=1"
         "&supportcrypto=1",
         TR_PRIsv_ARG(announce_sv),
-        announce_sv.find('?') == announce_sv.npos ? '?' : '&',
+        announce_sv.find('?') == std::string_view::npos ? '?' : '&',
         std::data(escaped_info_hash),
         TR_PRIsv_ARG(req->peer_id),
         req->port,
@@ -154,13 +154,13 @@ static void verboseLog(std::string_view description, tr_direction direction, std
     out << description << std::endl << "[raw]"sv << direction_sv;
     for (unsigned char ch : message)
     {
-        if (isprint(ch))
+        if (isprint(ch) != 0)
         {
             out << ch;
         }
         else
         {
-            out << "\\x"sv << std::hex << std::setw(2) << std::setfill('0') << unsigned(ch) << std::dec << std::setw(1)
+            out << R"(\x)" << std::hex << std::setw(2) << std::setfill('0') << unsigned(ch) << std::dec << std::setw(1)
                 << std::setfill(' ');
         }
     }
diff --git a/libtransmission/announcer-udp.cc b/libtransmission/announcer-udp.cc
index 3b01eef98..255ca575a 100644
--- a/libtransmission/announcer-udp.cc
+++ b/libtransmission/announcer-udp.cc
@@ -450,7 +450,7 @@ struct tau_tracker
     }
 };
 
-static void tau_tracker_upkeep(struct tau_tracker*);
+static void tau_tracker_upkeep(struct tau_tracker* /*tracker*/);
 
 static void tau_tracker_on_dns(int errcode, struct evutil_addrinfo* addr, void* vtracker)
 {
diff --git a/libtransmission/announcer.cc b/libtransmission/announcer.cc
index c3b12bd7a..333f2fb52 100644
--- a/libtransmission/announcer.cc
+++ b/libtransmission/announcer.cc
@@ -761,7 +761,7 @@ static void tier_announce_event_push(tr_tier* tier, tr_announce_event e, time_t
          * dump everything leading up to it except "completed" */
         if (e == TR_ANNOUNCE_EVENT_STOPPED)
         {
-            bool has_completed = std::count(std::begin(events), std::end(events), TR_ANNOUNCE_EVENT_COMPLETED);
+            bool has_completed = std::count(std::begin(events), std::end(events), TR_ANNOUNCE_EVENT_COMPLETED) != 0;
             events.clear();
             if (has_completed)
             {
@@ -885,7 +885,7 @@ void tr_announcerRemoveTorrent(tr_announcer* announcer, tr_torrent* tor)
             auto const e = TR_ANNOUNCE_EVENT_STOPPED;
             auto* req = announce_request_new(announcer, tor, &tier, e);
 
-            if (announcer->stops.count(req))
+            if (announcer->stops.count(req) != 0U)
             {
                 delete req;
             }
@@ -1593,8 +1593,8 @@ static tr_tracker_view trackerView(tr_torrent const& tor, int tier_index, tr_tie
     }
     else
     {
-        view.hasScraped = tier.lastScrapeTime;
-        if (view.hasScraped != 0)
+        view.hasScraped = tier.lastScrapeTime != 0;
+        if (view.hasScraped)
         {
             view.lastScrapeTime = tier.lastScrapeTime;
             view.lastScrapeSucceeded = tier.lastScrapeSucceeded;
@@ -1622,8 +1622,8 @@ static tr_tracker_view trackerView(tr_torrent const& tor, int tier_index, tr_tie
 
         view.lastAnnounceStartTime = tier.lastAnnounceStartTime;
 
-        view.hasAnnounced = tier.lastAnnounceTime;
-        if (view.hasAnnounced != 0)
+        view.hasAnnounced = tier.lastAnnounceTime != 0;
+        if (view.hasAnnounced)
         {
             view.lastAnnounceTime = tier.lastAnnounceTime;
             view.lastAnnounceSucceeded = tier.lastAnnounceSucceeded;
diff --git a/libtransmission/block-info.cc b/libtransmission/block-info.cc
index b9a3f4b07..7fd87b8cc 100644
--- a/libtransmission/block-info.cc
+++ b/libtransmission/block-info.cc
@@ -46,10 +46,10 @@ void tr_block_info::initSizes(uint64_t total_size_in, uint64_t piece_size_in)
     n_pieces = (total_size + piece_size - 1) / piece_size;
 
     auto remainder = total_size % piece_size;
-    final_piece_size = remainder ? remainder : piece_size;
+    final_piece_size = remainder != 0U ? remainder : piece_size;
 
     remainder = total_size % block_size;
-    final_block_size = remainder ? remainder : block_size;
+    final_block_size = remainder != 0U ? remainder : block_size;
 
     if (block_size != 0)
     {
diff --git a/libtransmission/clients.cc b/libtransmission/clients.cc
index cae0bcc9f..d446825c5 100644
--- a/libtransmission/clients.cc
+++ b/libtransmission/clients.cc
@@ -235,8 +235,8 @@ bool decodeBitCometClient(char* buf, size_t buflen, std::string_view peer_id)
 
     bool const is_bitlord = std::string_view(std::data(peer_id) + 6, 4) == "LORD"sv;
     auto const name = is_bitlord ? "BitLord"sv : "BitComet"sv;
-    int const major = peer_id[4];
-    int const minor = peer_id[5];
+    int const major = uint8_t(peer_id[4]);
+    int const minor = uint8_t(peer_id[5]);
 
     std::tie(buf, buflen) = buf_append(buf, buflen, name, ' ', mod, major, '.');
     tr_snprintf(buf, buflen, "%02d", minor);
@@ -683,7 +683,7 @@ char* tr_clientForId(char* buf, size_t buflen, tr_peer_id_t peer_id)
         {
             char const c = peer_id[i];
 
-            if (isprint((unsigned char)c))
+            if (isprint((unsigned char)c) != 0)
             {
                 *walk++ = c;
             }
diff --git a/libtransmission/crypto-utils-ccrypto.cc b/libtransmission/crypto-utils-ccrypto.cc
index 5561f8266..650c05a93 100644
--- a/libtransmission/crypto-utils-ccrypto.cc
+++ b/libtransmission/crypto-utils-ccrypto.cc
@@ -20,7 +20,7 @@
 
 #define TR_CRYPTO_DH_SECRET_FALLBACK
 #define TR_CRYPTO_X509_FALLBACK
-#include "crypto-utils-fallback.cc"
+#include "crypto-utils-fallback.cc" // NOLINT(bugprone-suspicious-include)
 
 /***
 ****
diff --git a/libtransmission/crypto-utils-cyassl.cc b/libtransmission/crypto-utils-cyassl.cc
index c8f9576a5..136b2a4ec 100644
--- a/libtransmission/crypto-utils-cyassl.cc
+++ b/libtransmission/crypto-utils-cyassl.cc
@@ -32,7 +32,7 @@
 
 #define TR_CRYPTO_DH_SECRET_FALLBACK
 #define TR_CRYPTO_X509_FALLBACK
-#include "crypto-utils-fallback.cc"
+#include "crypto-utils-fallback.cc" // NOLINT(bugprone-suspicious-include)
 
 struct tr_dh_ctx
 {
diff --git a/libtransmission/crypto-utils-openssl.cc b/libtransmission/crypto-utils-openssl.cc
index 63573fb35..d652f313a 100644
--- a/libtransmission/crypto-utils-openssl.cc
+++ b/libtransmission/crypto-utils-openssl.cc
@@ -25,7 +25,7 @@
 #include "utils.h"
 
 #define TR_CRYPTO_DH_SECRET_FALLBACK
-#include "crypto-utils-fallback.cc"
+#include "crypto-utils-fallback.cc" // NOLINT(bugprone-suspicious-include)
 
 /***
 ****
diff --git a/libtransmission/crypto-utils-polarssl.cc b/libtransmission/crypto-utils-polarssl.cc
index 25faef593..7f4d9a0ff 100644
--- a/libtransmission/crypto-utils-polarssl.cc
+++ b/libtransmission/crypto-utils-polarssl.cc
@@ -30,7 +30,7 @@
 
 #define TR_CRYPTO_DH_SECRET_FALLBACK
 #define TR_CRYPTO_X509_FALLBACK
-#include "crypto-utils-fallback.cc"
+#include "crypto-utils-fallback.cc" // NOLINT(bugprone-suspicious-include)
 
 /***
 ****
diff --git a/libtransmission/file-posix.cc b/libtransmission/file-posix.cc
index 94d1fea96..883f7b6a1 100644
--- a/libtransmission/file-posix.cc
+++ b/libtransmission/file-posix.cc
@@ -4,7 +4,7 @@
 // License text can be found in the licenses/ folder.
 
 #undef _GNU_SOURCE
-#define _GNU_SOURCE
+#define _GNU_SOURCE // NOLINT
 
 #include <algorithm>
 #include <array>
@@ -14,17 +14,17 @@
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
+#include <string_view>
+#include <vector>
+
 #include <dirent.h>
 #include <fcntl.h> /* O_LARGEFILE, posix_fadvise(), [posix_]fallocate(), fcntl() */
 #include <libgen.h> /* basename(), dirname() */
-#include <string_view>
-#include <unistd.h> /* lseek(), write(), ftruncate(), pread(), pwrite(), pathconf(), etc */
-#include <vector>
-
 #include <sys/file.h> /* flock() */
 #include <sys/mman.h> /* mmap(), munmap() */
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <unistd.h> /* lseek(), write(), ftruncate(), pread(), pwrite(), pathconf(), etc */
 
 #ifdef HAVE_XFS_XFS_H
 #include <xfs/xfs.h>
diff --git a/libtransmission/log.cc b/libtransmission/log.cc
index b9a883fc1..8d5e29d99 100644
--- a/libtransmission/log.cc
+++ b/libtransmission/log.cc
@@ -22,8 +22,7 @@
 
 using namespace std::literals;
 
-tr_log_level __tr_message_level = TR_LOG_ERROR;
-
+static tr_log_level tr_message_level = TR_LOG_ERROR;
 static bool myQueueEnabled = false;
 static tr_log_message* myQueue = nullptr;
 static tr_log_message** myQueueTail = &myQueue;
@@ -45,7 +44,7 @@ static inline bool IsDebuggerPresent()
 
 tr_log_level tr_logGetLevel()
 {
-    return __tr_message_level;
+    return tr_message_level;
 }
 
 /***
@@ -84,7 +83,7 @@ tr_sys_file_t tr_logGetFile()
 
 void tr_logSetLevel(tr_log_level level)
 {
-    __tr_message_level = level;
+    tr_message_level = level;
 }
 
 void tr_logSetQueueEnabled(bool isEnabled)
diff --git a/libtransmission/peer-mgr-active-requests.cc b/libtransmission/peer-mgr-active-requests.cc
index 6e69123ff..65dc49932 100644
--- a/libtransmission/peer-mgr-active-requests.cc
+++ b/libtransmission/peer-mgr-active-requests.cc
@@ -151,7 +151,7 @@ std::vector<tr_block_index_t> ActiveRequests::remove(tr_peer const* peer)
     auto const key = peer_at{ const_cast<tr_peer*>(peer), 0 };
     for (auto const& [block, peers_at] : impl_->blocks_)
     {
-        if (peers_at.count(key))
+        if (peers_at.count(key) != 0U)
         {
             removed.push_back(block);
         }
@@ -194,7 +194,7 @@ std::vector<tr_peer*> ActiveRequests::remove(tr_block_index_t block)
 bool ActiveRequests::has(tr_block_index_t block, tr_peer const* peer) const
 {
     auto const it = impl_->blocks_.find(block);
-    return it != std::end(impl_->blocks_) && it->second.count(peer_at{ const_cast<tr_peer*>(peer), 0 });
+    return it != std::end(impl_->blocks_) && (it->second.count(peer_at{ const_cast<tr_peer*>(peer), 0 }) != 0U);
 }
 
 // count how many peers we're asking for `block`
diff --git a/libtransmission/peer-mgr.cc b/libtransmission/peer-mgr.cc
index f8c6c9d51..ca78b8b23 100644
--- a/libtransmission/peer-mgr.cc
+++ b/libtransmission/peer-mgr.cc
@@ -6,6 +6,7 @@
 #include <algorithm>
 #include <cerrno> /* error codes ERANGE, ... */
 #include <climits> /* INT_MAX */
+#include <cmath>
 #include <cstdlib> /* qsort */
 #include <ctime> // time_t
 #include <iterator> // std::back_inserter
@@ -339,7 +340,7 @@ static void swarmFree(tr_swarm* s)
     delete s;
 }
 
-static void peerCallbackFunc(tr_peer*, tr_peer_event const*, void*);
+static void peerCallbackFunc(tr_peer* /*peer*/, tr_peer_event const* /*e*/, void* /*vs*/);
 
 static void rebuildWebseedArray(tr_swarm* s, tr_torrent* tor)
 {
@@ -681,7 +682,7 @@ static void addStrike(tr_swarm* s, tr_peer* peer)
     }
 }
 
-static void peerSuggestedPiece(tr_swarm* /*s*/, tr_peer* /*peer*/, tr_piece_index_t /*pieceIndex*/, int /*isFastAllowed*/)
+static void peerSuggestedPiece(tr_swarm* /*s*/, tr_peer* /*peer*/, tr_piece_index_t /*pieceIndex*/, bool /*isFastAllowed*/)
 {
 #if 0
 
@@ -1399,10 +1400,10 @@ int tr_peerMgrGetPeers(tr_torrent const* tor, tr_pex** setme_pex, uint8_t af, ui
     return count;
 }
 
-static void atomPulse(evutil_socket_t, short, void*);
-static void bandwidthPulse(evutil_socket_t, short, void*);
-static void rechokePulse(evutil_socket_t, short, void*);
-static void reconnectPulse(evutil_socket_t, short, void*);
+static void atomPulse(evutil_socket_t, short /*unused*/, void* /*vmgr*/);
+static void bandwidthPulse(evutil_socket_t, short /*unused*/, void* /*vmgr*/);
+static void rechokePulse(evutil_socket_t, short /*unused*/, void* /*vmgr*/);
+static void reconnectPulse(evutil_socket_t, short /*unused*/, void* /*vmgr*/);
 
 static struct event* createTimer(tr_session* session, int msec, event_callback_fn callback, void* cbdata)
 {
@@ -1450,7 +1451,7 @@ void tr_peerMgrStartTorrent(tr_torrent* tor)
     tr_timerAddMsec(s->manager->rechokeTimer, 100);
 }
 
-static void removeAllPeers(tr_swarm*);
+static void removeAllPeers(tr_swarm* /*swarm*/);
 
 static void stopSwarm(tr_swarm* swarm)
 {
@@ -2297,7 +2298,7 @@ static bool shouldPeerBeClosed(tr_swarm const* s, tr_peer const* peer, int peerC
     /* disconnect if it's been too long since piece data has been transferred.
      * this is on a sliding scale based on number of available peers... */
     {
-        auto const relaxStrictnessIfFewerThanN = int(getMaxPeerCount(tor) * 0.9 + 0.5);
+        auto const relaxStrictnessIfFewerThanN = std::lround(getMaxPeerCount(tor) * 0.9);
         /* if we have >= relaxIfFewerThan, strictness is 100%.
          * if we have zero connections, strictness is 0% */
         float const strictness = peerCount >= relaxStrictnessIfFewerThanN ? 1.0 :
diff --git a/libtransmission/peer-msgs.cc b/libtransmission/peer-msgs.cc
index 3d1601150..8cb410010 100644
--- a/libtransmission/peer-msgs.cc
+++ b/libtransmission/peer-msgs.cc
@@ -1408,7 +1408,7 @@ static ReadState readBtLength(tr_peerMsgsImpl* msgs, struct evbuffer* inbuf, siz
     return READ_NOW;
 }
 
-static ReadState readBtMessage(tr_peerMsgsImpl*, struct evbuffer*, size_t);
+static ReadState readBtMessage(tr_peerMsgsImpl* /*msgs*/, struct evbuffer* /*inbuf*/, size_t /*inlen*/);
 
 static ReadState readBtId(tr_peerMsgsImpl* msgs, struct evbuffer* inbuf, size_t inlen)
 {
diff --git a/libtransmission/platform-quota.cc b/libtransmission/platform-quota.cc
index 3103d7aae..48a1e3d24 100644
--- a/libtransmission/platform-quota.cc
+++ b/libtransmission/platform-quota.cc
@@ -220,7 +220,7 @@ static std::string getblkdev(std::string_view path)
         }
 
         auto const pos = path.rfind('/');
-        if (pos == path.npos)
+        if (pos == std::string_view::npos)
         {
             return {};
         }
@@ -459,7 +459,7 @@ static struct tr_disk_space getDiskSpace(char const* path)
 #elif defined(HAVE_STATVFS)
 
     struct statvfs buf;
-    return statvfs(path, &buf) ?
+    return statvfs(path, &buf) != 0 ?
         (struct tr_disk_space){ -1, -1 } :
         (struct tr_disk_space){ (int64_t)buf.f_bavail * (int64_t)buf.f_frsize, (int64_t)buf.f_blocks * (int64_t)buf.f_frsize };
 
@@ -479,7 +479,7 @@ tr_device_info tr_device_info_create(std::string_view path)
 #ifndef _WIN32
     out.device = getblkdev(out.path);
     auto const* const fstype = getfstype(out.path.c_str());
-    out.fstype = fstype ? fstype : "";
+    out.fstype = fstype != nullptr ? fstype : "";
 #endif
     return out;
 }
diff --git a/libtransmission/platform.cc b/libtransmission/platform.cc
index 57fa1d3c9..a5111acee 100644
--- a/libtransmission/platform.cc
+++ b/libtransmission/platform.cc
@@ -253,7 +253,7 @@ static std::string getXdgEntryFromUserDirs(std::string_view key)
     }
 
     // search for key="val" and extract val
-    auto const search = tr_strvJoin(key, "=\""sv);
+    auto const search = tr_strvJoin(key, R"(=")");
     auto begin = std::search(std::begin(content), std::end(content), std::begin(search), std::end(search));
     if (begin == std::end(content))
     {
diff --git a/libtransmission/resume.cc b/libtransmission/resume.cc
index dad32777f..c7ec73823 100644
--- a/libtransmission/resume.cc
+++ b/libtransmission/resume.cc
@@ -415,7 +415,7 @@ static uint64_t loadFilenames(tr_variant* dict, tr_torrent* tor)
 
 static void bitfieldToRaw(tr_bitfield const& b, tr_variant* benc)
 {
-    if (b.hasNone() || std::empty(b))
+    if (b.hasNone() || (std::empty(b) != 0U))
     {
         tr_variantInitStr(benc, "none"sv);
     }
diff --git a/libtransmission/rpc-server.cc b/libtransmission/rpc-server.cc
index 70e214184..67a329dca 100644
--- a/libtransmission/rpc-server.cc
+++ b/libtransmission/rpc-server.cc
@@ -724,9 +724,9 @@ static auto parseWhitelist(std::string_view whitelist)
         auto const pos = whitelist.find_first_of(" ,;"sv);
         auto const token = tr_strvStrip(whitelist.substr(0, pos));
         list.emplace_back(token);
-        whitelist = pos == whitelist.npos ? ""sv : whitelist.substr(pos + 1);
+        whitelist = pos == std::string_view::npos ? ""sv : whitelist.substr(pos + 1);
 
-        if (token.find_first_of("+-"sv) != token.npos)
+        if (token.find_first_of("+-"sv) != std::string_view::npos)
         {
             tr_logAddNamedInfo(
                 MyName,
diff --git a/libtransmission/rpcimpl.cc b/libtransmission/rpcimpl.cc
index f527c55fc..d44b70a4f 100644
--- a/libtransmission/rpcimpl.cc
+++ b/libtransmission/rpcimpl.cc
@@ -812,7 +812,7 @@ static void initField(tr_torrent const* const tor, tr_stat const* const st, tr_v
             tr_variantInitList(initme, n);
             for (tr_file_index_t i = 0; i < n; ++i)
             {
-                tr_variantListAddInt(initme, tr_torrentFile(tor, i).wanted);
+                tr_variantListAddBool(initme, tr_torrentFile(tor, i).wanted);
             }
         }
         break;
diff --git a/libtransmission/session.cc b/libtransmission/session.cc
index dd8e3196a..e9035b323 100644
--- a/libtransmission/session.cc
+++ b/libtransmission/session.cc
@@ -572,7 +572,7 @@ static void onSaveTimer(evutil_socket_t /*fd*/, short /*what*/, void* vsession)
 ****
 ***/
 
-static void tr_sessionInitImpl(void*);
+static void tr_sessionInitImpl(void* /*vdata*/);
 
 struct init_data
 {
@@ -757,7 +757,7 @@ static void tr_sessionInitImpl(void* vdata)
     data->done = true;
 }
 
-static void turtleBootstrap(tr_session*, struct tr_turtle_info*);
+static void turtleBootstrap(tr_session* /*session*/, struct tr_turtle_info* /*turtle*/);
 static void setPeerPort(tr_session* session, tr_port port);
 
 static void sessionSetImpl(void* vdata)
@@ -1142,7 +1142,7 @@ void tr_sessionSetDownloadDir(tr_session* session, char const* dir)
 {
     TR_ASSERT(tr_isSession(session));
 
-    session->setDownloadDir(dir ? dir : "");
+    session->setDownloadDir(dir != nullptr ? dir : "");
 }
 
 char const* tr_sessionGetDownloadDir(tr_session const* session)
@@ -1178,7 +1178,7 @@ void tr_sessionSetIncompleteDir(tr_session* session, char const* dir)
 {
     TR_ASSERT(tr_isSession(session));
 
-    session->setIncompleteDir(dir ? dir : "");
+    session->setIncompleteDir(dir != nullptr ? dir : "");
 }
 
 char const* tr_sessionGetIncompleteDir(tr_session const* session)
@@ -1801,7 +1801,7 @@ std::vector<tr_torrent*> tr_sessionGetTorrents(tr_session* session)
     return torrents;
 }
 
-static void closeBlocklists(tr_session*);
+static void closeBlocklists(tr_session* /*session*/);
 
 static void sessionCloseImplWaitForIdleUdp(evutil_socket_t fd, short what, void* vsession);
 
@@ -2042,7 +2042,7 @@ static void sessionLoadTorrents(void* vdata)
     }
 
     int const n = std::size(torrents);
-    data->torrents = tr_new(tr_torrent*, n);
+    data->torrents = tr_new(tr_torrent*, n); // NOLINT(bugprone-sizeof-expression)
     std::copy(std::begin(torrents), std::end(torrents), data->torrents);
 
     if (n != 0)
@@ -2454,7 +2454,7 @@ bool tr_sessionIsAddressBlocked(tr_session const* session, tr_address const* add
 
 void tr_blocklistSetURL(tr_session* session, char const* url)
 {
-    session->setBlocklistUrl(url ? url : "");
+    session->setBlocklistUrl(url != nullptr ? url : "");
 }
 
 char const* tr_blocklistGetURL(tr_session const* session)
@@ -2518,7 +2518,7 @@ void tr_sessionSetRPCUrl(tr_session* session, char const* url)
 {
     TR_ASSERT(tr_isSession(session));
 
-    tr_rpcSetUrl(session->rpc_server_.get(), url ? url : "");
+    tr_rpcSetUrl(session->rpc_server_.get(), url != nullptr ? url : "");
 }
 
 char const* tr_sessionGetRPCUrl(tr_session const* session)
@@ -2540,7 +2540,7 @@ void tr_sessionSetRPCWhitelist(tr_session* session, char const* whitelist)
 {
     TR_ASSERT(tr_isSession(session));
 
-    session->setRpcWhitelist(whitelist ? whitelist : "");
+    session->setRpcWhitelist(whitelist != nullptr ? whitelist : "");
 }
 
 char const* tr_sessionGetRPCWhitelist(tr_session const* session)
@@ -2568,7 +2568,7 @@ void tr_sessionSetRPCPassword(tr_session* session, char const* password)
 {
     TR_ASSERT(tr_isSession(session));
 
-    tr_rpcSetPassword(session->rpc_server_.get(), password ? password : "");
+    tr_rpcSetPassword(session->rpc_server_.get(), password != nullptr ? password : "");
 }
 
 char const* tr_sessionGetRPCPassword(tr_session const* session)
@@ -2582,7 +2582,7 @@ void tr_sessionSetRPCUsername(tr_session* session, char const* username)
 {
     TR_ASSERT(tr_isSession(session));
 
-    tr_rpcSetUsername(session->rpc_server_.get(), username ? username : "");
+    tr_rpcSetUsername(session->rpc_server_.get(), username != nullptr ? username : "");
 }
 
 char const* tr_sessionGetRPCUsername(tr_session const* session)
@@ -2638,7 +2638,7 @@ void tr_sessionSetScript(tr_session* session, TrScript type, char const* script)
     TR_ASSERT(tr_isSession(session));
     TR_ASSERT(type < TR_SCRIPT_N_TYPES);
 
-    session->setScript(type, script ? script : "");
+    session->setScript(type, script != nullptr ? script : "");
 }
 
 char const* tr_sessionGetScript(tr_session const* session, TrScript type)
diff --git a/libtransmission/subprocess-posix.cc b/libtransmission/subprocess-posix.cc
index cd6f5617d..66e984c93 100644
--- a/libtransmission/subprocess-posix.cc
+++ b/libtransmission/subprocess-posix.cc
@@ -78,7 +78,7 @@ static bool tr_spawn_async_in_child(
     return true;
 
 FAIL:
-    (void)!write(pipe_fd, &errno, sizeof(errno));
+    (void)write(pipe_fd, &errno, sizeof(errno));
     return false;
 }
 
diff --git a/libtransmission/torrent-ctor.cc b/libtransmission/torrent-ctor.cc
index 3581bad0b..d58666ed8 100644
--- a/libtransmission/torrent-ctor.cc
+++ b/libtransmission/torrent-ctor.cc
@@ -86,7 +86,7 @@ bool tr_ctorSetMetainfoFromFile(tr_ctor* ctor, std::string const& filename, tr_e
 
 bool tr_ctorSetMetainfoFromFile(tr_ctor* ctor, char const* filename, tr_error** error)
 {
-    return tr_ctorSetMetainfoFromFile(ctor, std::string{ filename ? filename : "" }, error);
+    return tr_ctorSetMetainfoFromFile(ctor, std::string{ filename != nullptr ? filename : "" }, error);
 }
 
 bool tr_ctorSetMetainfo(tr_ctor* ctor, char const* metainfo, size_t len, tr_error** error)
@@ -100,7 +100,7 @@ bool tr_ctorSetMetainfo(tr_ctor* ctor, char const* metainfo, size_t len, tr_erro
 bool tr_ctorSetMetainfoFromMagnetLink(tr_ctor* ctor, char const* magnet_link, tr_error** error)
 {
     ctor->torrent_filename.clear();
-    return ctor->metainfo.parseMagnet(magnet_link ? magnet_link : "", error);
+    return ctor->metainfo.parseMagnet(magnet_link != nullptr ? magnet_link : "", error);
 }
 
 std::string_view tr_ctorGetContents(tr_ctor const* ctor)
@@ -218,12 +218,12 @@ void tr_ctorSetDownloadDir(tr_ctor* ctor, tr_ctorMode mode, char const* director
     TR_ASSERT(ctor != nullptr);
     TR_ASSERT(mode == TR_FALLBACK || mode == TR_FORCE);
 
-    ctor->optional_args[mode].download_dir.assign(directory ? directory : "");
+    ctor->optional_args[mode].download_dir.assign(directory != nullptr ? directory : "");
 }
 
 void tr_ctorSetIncompleteDir(tr_ctor* ctor, char const* directory)
 {
-    ctor->incomplete_dir.assign(directory ? directory : "");
+    ctor->incomplete_dir.assign(directory != nullptr ? directory : "");
 }
 
 bool tr_ctorGetPeerLimit(tr_ctor const* ctor, tr_ctorMode mode, uint16_t* setme)
diff --git a/libtransmission/torrent-metainfo.cc b/libtransmission/torrent-metainfo.cc
index 7dc3e0d03..5412922e2 100644
--- a/libtransmission/torrent-metainfo.cc
+++ b/libtransmission/torrent-metainfo.cc
@@ -196,7 +196,7 @@ static bool appendSanitizedComponent(std::string& out, std::string_view in, bool
     // remove trailing spaces and '.'
     auto constexpr trailing_test = [](unsigned char ch)
     {
-        return isspace(ch) || ch == '.';
+        return (isspace(ch) != 0) || ch == '.';
     };
     auto const rit = std::find_if_not(std::rbegin(in), std::rend(in), trailing_test);
     in.remove_suffix(std::distance(std::rbegin(in), rit));
diff --git a/libtransmission/torrent.cc b/libtransmission/torrent.cc
index 2d69a0b5d..d7a85127c 100644
--- a/libtransmission/torrent.cc
+++ b/libtransmission/torrent.cc
@@ -111,7 +111,7 @@ tr_torrent* tr_torrentFindFromMetainfo(tr_session* session, tr_torrent_metainfo
 tr_torrent* tr_torrentFindFromMagnetLink(tr_session* session, char const* magnet_link)
 {
     auto mm = tr_magnet_metainfo{};
-    return mm.parseMagnet(magnet_link ? magnet_link : "") ? session->getTorrent(mm.infoHash()) : nullptr;
+    return mm.parseMagnet(magnet_link != nullptr ? magnet_link : "") ? session->getTorrent(mm.infoHash()) : nullptr;
 }
 
 tr_torrent* tr_torrentFindFromObfuscatedHash(tr_session* session, tr_sha1_digest_t const& obfuscated_hash)
@@ -1216,7 +1216,7 @@ static void tr_torrentResetTransferStats(tr_torrent* tor)
 ***/
 
 #ifdef TR_ENABLE_ASSERTS
-static bool queueIsSequenced(tr_session*);
+static bool queueIsSequenced(tr_session* /*session*/);
 #endif
 
 static void freeTorrent(tr_torrent* tor)
@@ -1570,7 +1570,7 @@ struct remove_data
     tr_fileFunc deleteFunc;
 };
 
-static void tr_torrentDeleteLocalData(tr_torrent*, tr_fileFunc);
+static void tr_torrentDeleteLocalData(tr_torrent* /*tor*/, tr_fileFunc /*func*/);
 
 static void removeTorrent(void* vdata)
 {
@@ -2010,7 +2010,7 @@ bool tr_torrentSetAnnounceList(tr_torrent* tor, char const* const* announce_urls
     auto const lock = tor->unique_lock();
 
     auto announce_list = tr_announce_list();
-    if (!announce_list.set(announce_urls, tiers, n) || !announce_list.save(tor->torrentFile()))
+    if ((announce_list.set(announce_urls, tiers, n) == 0U) || !announce_list.save(tor->torrentFile()))
     {
         return false;
     }
@@ -2443,7 +2443,7 @@ void tr_torrentSetLocation(
     TR_ASSERT(tr_isTorrent(tor));
     TR_ASSERT(!tr_str_is_empty(location));
 
-    return tor->setLocation(location ? location : "", move_from_old_location, setme_progress, setme_state);
+    return tor->setLocation(location != nullptr ? location : "", move_from_old_location, setme_progress, setme_state);
 }
 
 std::string_view tr_torrent::primaryMimeType() const
diff --git a/libtransmission/tr-dht.cc b/libtransmission/tr-dht.cc
index 91c956a29..2b615f76f 100644
--- a/libtransmission/tr-dht.cc
+++ b/libtransmission/tr-dht.cc
@@ -9,6 +9,9 @@
 #include <cstdlib> /* atoi() */
 #include <cstring> /* memcpy(), memset(), memchr(), strlen() */
 #include <ctime>
+#include <fstream>
+#include <sstream>
+#include <string>
 #include <string_view>
 #include <thread>
 
@@ -129,6 +132,42 @@ static void bootstrap_from_name(char const* name, tr_port port, int af)
     freeaddrinfo(info);
 }
 
+static void dht_boostrap_from_file(tr_session* session)
+{
+    if (bootstrap_done(session, 0))
+    {
+        return;
+    }
+
+    // check for a manual bootstrap file.
+    auto const bootstrap_file = tr_strvPath(session->config_dir, "dht.bootstrap");
+    auto in = std::ifstream{ bootstrap_file };
+    if (!in.is_open())
+    {
+        return;
+    }
+
+    // format is each line has address, a space char, and port number
+    tr_logAddNamedInfo("DHT", "Attempting manual bootstrap");
+    auto line = std::string{};
+    while (!bootstrap_done(session, 0) && std::getline(in, line))
+    {
+        auto line_stream = std::istringstream{ line };
+        auto addrstr = std::string{};
+        auto port = tr_port{};
+        line_stream >> addrstr >> port;
+
+        if (line_stream.bad() || std::empty(addrstr) || port <= 0)
+        {
+            tr_logAddNamedError("DHT", "Couldn't parse line: \"%s\"", line.c_str());
+        }
+        else
+        {
+            bootstrap_from_name(addrstr.c_str(), port, bootstrap_af(session_));
+        }
+    }
+}
+
 static void dht_bootstrap(void* closure)
 {
     auto* cl = static_cast<struct bootstrap_closure*>(closure);
@@ -198,48 +237,7 @@ static void dht_bootstrap(void* closure)
 
     if (!bootstrap_done(cl->session, 0))
     {
-        auto const bootstrap_file = tr_strvPath(cl->session->config_dir, "dht.bootstrap");
-
-        tr_sys_file_t const f = tr_sys_file_open(bootstrap_file.c_str(), TR_SYS_FILE_READ, 0, nullptr);
-
-        if (f != TR_BAD_SYS_FILE)
-        {
-            tr_logAddNamedInfo("DHT", "Attempting manual bootstrap");
-
-            for (;;)
-            {
-                char buf[201];
-                if (!tr_sys_file_read_line(f, buf, 200, nullptr))
-                {
-                    break;
-                }
-
-                auto* p = static_cast<char*>(memchr(buf, ' ', strlen(buf)));
-                int port = 0;
-
-                if (p != nullptr)
-                {
-                    port = atoi(p + 1);
-                }
-
-                if (p == nullptr || port <= 0 || port >= 0x10000)
-                {
-                    tr_logAddNamedError("DHT", "Couldn't parse %s", buf);
-                    continue;
-                }
-
-                *p = '\0';
-
-                bootstrap_from_name(buf, port, bootstrap_af(session_));
-
-                if (bootstrap_done(cl->session, 0))
-                {
-                    break;
-                }
-            }
-
-            tr_sys_file_close(f, nullptr);
-        }
+        dht_boostrap_from_file(cl->session);
     }
 
     if (!bootstrap_done(cl->session, 0))
diff --git a/libtransmission/tr-lpd.cc b/libtransmission/tr-lpd.cc
index 7d316c2f3..cfaac13a0 100644
--- a/libtransmission/tr-lpd.cc
+++ b/libtransmission/tr-lpd.cc
@@ -46,7 +46,7 @@ static auto constexpr SIZEOF_HASH_STRING = TR_SHA1_DIGEST_STRLEN;
 *
 */
 
-static void event_callback(evutil_socket_t, short, void*);
+static void event_callback(evutil_socket_t, short /*type*/, void* /*unused*/);
 
 static auto constexpr UpkeepIntervalSecs = int{ 5 };
 
@@ -239,7 +239,7 @@ static bool lpd_extractParam(char const* const str, char const* const name, int
 /**
 * @} */
 
-static void on_upkeep_timer(evutil_socket_t, short, void*);
+static void on_upkeep_timer(evutil_socket_t, short /*unused*/, void* /*unused*/);
 
 /**
 * @brief Initializes Local Peer Discovery for this node
diff --git a/libtransmission/tr-udp.cc b/libtransmission/tr-udp.cc
index 363822142..6497cd212 100644
--- a/libtransmission/tr-udp.cc
+++ b/libtransmission/tr-udp.cc
@@ -109,7 +109,7 @@ void tr_udpSetSocketTOS(tr_session* session)
 {
     auto const tos = session->peerSocketTos();
 
-    if (tos)
+    if (tos != 0)
     {
         return;
     }
@@ -261,9 +261,7 @@ static void event_callback(evutil_socket_t s, [[maybe_unused]] short type, void*
         }
         else if (rc >= 8 && buf[0] == 0 && buf[1] == 0 && buf[2] == 0 && buf[3] <= 3)
         {
-            rc = tau_handle_message(session, buf, rc);
-
-            if (rc == 0)
+            if (!tau_handle_message(session, buf, rc))
             {
                 tr_logAddNamedDbg("UDP", "Couldn't parse UDP tracker packet.");
             }
@@ -272,9 +270,7 @@ static void event_callback(evutil_socket_t s, [[maybe_unused]] short type, void*
         {
             if (tr_sessionIsUTPEnabled(session))
             {
-                rc = tr_utpPacket(buf, rc, (struct sockaddr*)&from, fromlen, session);
-
-                if (rc == 0)
+                if (!tr_utpPacket(buf, rc, (struct sockaddr*)&from, fromlen, session))
                 {
                     tr_logAddNamedDbg("UDP", "Unexpected UDP packet");
                 }
diff --git a/libtransmission/tr-utp.cc b/libtransmission/tr-utp.cc
index 2146034e7..f870def08 100644
--- a/libtransmission/tr-utp.cc
+++ b/libtransmission/tr-utp.cc
@@ -42,14 +42,14 @@ bool UTP_Write(struct UTPSocket* socket, size_t count)
     return false;
 }
 
-int tr_utpPacket(
+bool tr_utpPacket(
     unsigned char const* /*buf*/,
     size_t /*buflen*/,
     sockaddr const* /*from*/,
     socklen_t /*fromlen*/,
     tr_session* /*ss*/)
 {
-    return -1;
+    return false;
 }
 
 struct UTPSocket* UTP_Create(
@@ -152,7 +152,7 @@ static void timer_callback(evutil_socket_t /*s*/, short /*type*/, void* vsession
     reset_timer(session);
 }
 
-int tr_utpPacket(unsigned char const* buf, size_t buflen, struct sockaddr const* from, socklen_t fromlen, tr_session* ss)
+bool tr_utpPacket(unsigned char const* buf, size_t buflen, struct sockaddr const* from, socklen_t fromlen, tr_session* ss)
 {
     if (!ss->isClosed && ss->utp_timer == nullptr)
     {
@@ -160,7 +160,7 @@ int tr_utpPacket(unsigned char const* buf, size_t buflen, struct sockaddr const*
 
         if (ss->utp_timer == nullptr)
         {
-            return -1;
+            return false;
         }
 
         reset_timer(ss);
diff --git a/libtransmission/tr-utp.h b/libtransmission/tr-utp.h
index 704a1e579..6aa811caf 100644
--- a/libtransmission/tr-utp.h
+++ b/libtransmission/tr-utp.h
@@ -10,7 +10,7 @@
 
 #include <cstddef> // size_t
 
-int tr_utpPacket(unsigned char const* buf, size_t buflen, struct sockaddr const* from, socklen_t fromlen, tr_session* ss);
+bool tr_utpPacket(unsigned char const* buf, size_t buflen, struct sockaddr const* from, socklen_t fromlen, tr_session* ss);
 
 void tr_utpClose(tr_session*);
 
diff --git a/libtransmission/trevent.cc b/libtransmission/trevent.cc
index 81d61639a..fdf8468f5 100644
--- a/libtransmission/trevent.cc
+++ b/libtransmission/trevent.cc
@@ -51,7 +51,7 @@ void lock_free(void* lock_, unsigned /*locktype*/)
 int lock_lock(unsigned mode, void* lock_)
 {
     auto* lock = static_cast<std::recursive_mutex*>(lock_);
-    if (mode & EVTHREAD_TRY)
+    if ((mode & EVTHREAD_TRY) != 0U)
     {
         auto const success = lock->try_lock();
         return success ? 0 : -1;
@@ -79,7 +79,7 @@ void cond_free(void* cond_)
 int cond_signal(void* cond_, int broadcast)
 {
     auto* cond = static_cast<std::condition_variable_any*>(cond_);
-    if (broadcast)
+    if (broadcast != 0)
     {
         cond->notify_all();
     }
@@ -206,7 +206,7 @@ static void libeventThreadFunc(tr_event_handle* events)
     events->base = base;
     events->work_queue_event = event_new(base, -1, 0, onWorkAvailable, events->session);
     events->session->event_base = base;
-    events->session->evdns_base = evdns_base_new(base, true);
+    events->session->evdns_base = evdns_base_new(base, EVDNS_BASE_INITIALIZE_NAMESERVERS);
     events->session->events = events;
 
     // loop until `tr_eventClose()` kills the loop
diff --git a/libtransmission/utils.cc b/libtransmission/utils.cc
index fdabb5f31..779269b98 100644
--- a/libtransmission/utils.cc
+++ b/libtransmission/utils.cc
@@ -164,15 +164,15 @@ char const* tr_strip_positional_args(char const* str)
     char const* in = str;
     size_t pos = 0;
 
-    for (; str && *str && pos + 1 < std::size(buf); ++str)
+    for (; (str != nullptr) && (*str != 0) && pos + 1 < std::size(buf); ++str)
     {
         buf[pos++] = *str;
 
-        if (*str == '%' && isdigit(str[1]))
+        if (*str == '%' && (isdigit(str[1]) != 0))
         {
             char const* tmp = str + 1;
 
-            while (isdigit(*tmp))
+            while (isdigit(*tmp) != 0)
             {
                 ++tmp;
             }
@@ -191,7 +191,7 @@ char const* tr_strip_positional_args(char const* str)
 
     buf[pos] = '\0';
 
-    return in && !strcmp(buf.data(), in) ? in : buf.data();
+    return (in != nullptr) && (strcmp(buf.data(), in) == 0) ? in : buf.data();
 }
 
 /**
@@ -743,7 +743,7 @@ std::string& tr_strvUtf8Clean(std::string_view cleanme, std::string& setme)
     else
     {
         auto* const tmp = to_utf8(cleanme);
-        setme.assign(tmp ? tmp : "");
+        setme.assign(tmp != nullptr ? tmp : "");
         tr_free(tmp);
     }
 
diff --git a/libtransmission/variant-benc.cc b/libtransmission/variant-benc.cc
index 0198ef553..34ec17e3c 100644
--- a/libtransmission/variant-benc.cc
+++ b/libtransmission/variant-benc.cc
@@ -66,7 +66,7 @@ std::optional<int64_t> ParseInt(std::string_view* benc)
     }
 
     // leading zeroes are not allowed
-    if ((walk[0] == '0' && isdigit(walk[1])) || (walk[0] == '-' && walk[1] == '0' && isdigit(walk[2])))
+    if ((walk[0] == '0' && (isdigit(walk[1]) != 0)) || (walk[0] == '-' && walk[1] == '0' && (isdigit(walk[2]) != 0)))
     {
         return {};
     }
diff --git a/libtransmission/variant-json.cc b/libtransmission/variant-json.cc
index 46db00c74..f424a4264 100644
--- a/libtransmission/variant-json.cc
+++ b/libtransmission/variant-json.cc
@@ -571,7 +571,7 @@ static void jsonStringFunc(tr_variant const* val, void* vdata)
             break;
 
         default:
-            if (isprint((unsigned char)sv.front()))
+            if (isprint((unsigned char)sv.front()) != 0)
             {
                 *outwalk++ = sv.front();
             }
diff --git a/libtransmission/variant.cc b/libtransmission/variant.cc
index 18d388895..6a08be1d3 100644
--- a/libtransmission/variant.cc
+++ b/libtransmission/variant.cc
@@ -5,7 +5,7 @@
 
 #if defined(HAVE_USELOCALE) && (!defined(_XOPEN_SOURCE) || _XOPEN_SOURCE < 700)
 #undef _XOPEN_SOURCE
-#define _XOPEN_SOURCE 700
+#define XOPEN_SOURCE 700 // NOLINT
 #endif
 
 #if defined(HAVE_USELOCALE) && !defined(_GNU_SOURCE)
@@ -479,7 +479,7 @@ void tr_variantInitStrView(tr_variant* v, std::string_view str)
 void tr_variantInitBool(tr_variant* v, bool value)
 {
     tr_variantInit(v, TR_VARIANT_TYPE_BOOL);
-    v->val.b = value != 0;
+    v->val.b = value;
 }
 
 void tr_variantInitReal(tr_variant* v, double value)
@@ -1105,7 +1105,7 @@ void tr_variantMergeDicts(tr_variant* target, tr_variant const* source)
 
             // if types differ, ensure that target will overwrite source
             auto const* const target_child = tr_variantDictFind(target, key);
-            if (target_child && !tr_variantIsType(target_child, val->type))
+            if ((target_child != nullptr) && !tr_variantIsType(target_child, val->type))
             {
                 tr_variantDictRemove(target, key);
             }
@@ -1237,7 +1237,7 @@ bool tr_variantFromBuf(tr_variant* setme, int opts, std::string_view buf, char c
     use_numeric_locale(&locale_ctx, "C");
 
     auto success = bool{};
-    if (opts & TR_VARIANT_PARSE_BENC)
+    if ((opts & TR_VARIANT_PARSE_BENC) != 0)
     {
         success = tr_variantParseBenc(*setme, opts, buf, setme_end, error);
     }
@@ -1245,7 +1245,7 @@ bool tr_variantFromBuf(tr_variant* setme, int opts, std::string_view buf, char c
     {
         // TODO: tr_variantParseJson() should take a tr_error* same as ParseBenc
         auto err = tr_variantParseJson(*setme, opts, buf, setme_end);
-        if (err)
+        if (err != 0)
         {
             tr_error_set(error, EILSEQ, "error parsing encoded data"sv);
         }
diff --git a/libtransmission/verify.cc b/libtransmission/verify.cc
index 773985a33..0f80301c5 100644
--- a/libtransmission/verify.cc
+++ b/libtransmission/verify.cc
@@ -38,7 +38,7 @@ static bool verifyTorrent(tr_torrent* tor, bool const* stopFlag)
     time_t lastSleptAt = 0;
     uint32_t piecePos = 0;
     tr_file_index_t fileIndex = 0;
-    tr_file_index_t prevFileIndex = !fileIndex;
+    tr_file_index_t prevFileIndex = ~0;
     tr_piece_index_t piece = 0;
     auto buffer = std::vector<std::byte>(1024 * 256);
     auto sha = tr_sha1_init();
diff --git a/libtransmission/watchdir.cc b/libtransmission/watchdir.cc
index dfcd3b2b6..ca7a84ad5 100644
--- a/libtransmission/watchdir.cc
+++ b/libtransmission/watchdir.cc
@@ -144,7 +144,7 @@ static void tr_watchdir_on_retry_timer(evutil_socket_t /*fd*/, short /*type*/, v
     TR_ASSERT(context != nullptr);
 
     auto* const retry = static_cast<tr_watchdir_retry*>(context);
-    tr_watchdir_t const handle = retry->handle;
+    auto const handle = retry->handle;
 
     if (tr_watchdir_process_impl(handle, retry->name) == TR_WATCHDIR_RETRY)
     {
@@ -325,7 +325,7 @@ void tr_watchdir_scan(tr_watchdir_t handle, std::unordered_set<std::string>* dir
     auto new_dir_entries = std::unordered_set<std::string>{};
     tr_error* error = nullptr;
 
-    tr_sys_dir_t const dir = tr_sys_dir_open(handle->path, &error);
+    auto const dir = tr_sys_dir_open(handle->path, &error);
     if (dir == TR_BAD_SYS_DIR)
     {
         log_error("Failed to open directory \"%s\" (%d): %s", handle->path, error->code, error->message);
diff --git a/libtransmission/web-utils.cc b/libtransmission/web-utils.cc
index 54a4d345c..9c0e66968 100644
--- a/libtransmission/web-utils.cc
+++ b/libtransmission/web-utils.cc
@@ -414,7 +414,7 @@ std::string tr_urlPercentDecode(std::string_view in)
         }
 
         in.remove_prefix(pos);
-        if (std::size(in) >= 3 && in[0] == '%' && std::isxdigit(in[1]) && std::isxdigit(in[2]))
+        if (std::size(in) >= 3 && in[0] == '%' && (std::isxdigit(in[1]) != 0) && (std::isxdigit(in[2]) != 0))
         {
             auto hexstr = std::array<char, 3>{ in[1], in[2], '\0' };
             auto const hex = strtoul(std::data(hexstr), nullptr, 16);
diff --git a/libtransmission/web.cc b/libtransmission/web.cc
index 9b999b740..93eff0711 100644
--- a/libtransmission/web.cc
+++ b/libtransmission/web.cc
@@ -150,7 +150,7 @@ static int sockoptfunction(void* vtask, curl_socket_t fd, curlsocktype /*purpose
 
 static CURLcode ssl_context_func(CURL* /*curl*/, void* ssl_ctx, void* /*user_data*/)
 {
-    tr_x509_store_t const cert_store = tr_ssl_get_x509_store(ssl_ctx);
+    auto const cert_store = tr_ssl_get_x509_store(ssl_ctx);
     if (cert_store == nullptr)
     {
         return CURLE_OK;
@@ -490,7 +490,7 @@ static void tr_webThreadFunc(void* vsession)
 
             auto numfds = int{};
             curl_multi_wait(multi, nullptr, 0, msec, &numfds);
-            if (!numfds)
+            if (numfds == 0)
             {
                 repeats++;
                 if (repeats > 1)
diff --git a/libtransmission/webseed.cc b/libtransmission/webseed.cc
index 33e5fa0d3..f85de4cee 100644
--- a/libtransmission/webseed.cc
+++ b/libtransmission/webseed.cc
@@ -309,7 +309,7 @@ static void on_content_changed(struct evbuffer* buf, struct evbuffer_cb_info con
                     session,
                     connection_succeeded,
                     new connection_succeeded_data{ w,
-                                                   real_url ? real_url : "",
+                                                   real_url != nullptr ? real_url : "",
                                                    task->piece_index,
                                                    task->piece_offset + task->blocks_done * task->block_size + len - 1 });
             }