diff --git a/libtransmission/ConvertUTF.c b/libtransmission/ConvertUTF.c
index 9a8fd68c8..517714503 100644
--- a/libtransmission/ConvertUTF.c
+++ b/libtransmission/ConvertUTF.c
@@ -44,8 +44,6 @@
 #endif
 #include <string.h> /* strlen () */
 
-#include "transmission.h"
-
 #include "ConvertUTF.h"
 
 static const int halfShift  = 10; /* used for shifting by 10 bits */
@@ -364,7 +362,7 @@ tr_utf8_validate (const char * str, size_t max_len, const char ** end)
     if (str == NULL)
         return false;
 
-    sourceEnd = source + (max_len == TR_BAD_SIZE ? strlen (str) : max_len);
+    sourceEnd = source + (max_len == ((size_t)-1) ? strlen (str) : max_len);
 
     if (source == sourceEnd)
     {
diff --git a/libtransmission/announcer-common.h b/libtransmission/announcer-common.h
index e86298a5a..fb965e347 100644
--- a/libtransmission/announcer-common.h
+++ b/libtransmission/announcer-common.h
@@ -21,21 +21,18 @@
 ****  SCRAPE
 ***/
 
-enum
-{
-    /* pick a number small enough for common tracker software:
-     *  - ocelot has no upper bound
-     *  - opentracker has an upper bound of 64
-     *  - udp protocol has an upper bound of 74
-     *  - xbtt has no upper bound
-     *
-     * This is only an upper bound: if the tracker complains about
-     * length, announcer will incrementally lower the batch size.
-     */
-    TR_MULTISCRAPE_MAX = 60
-};
+/* pick a number small enough for common tracker software:
+ *  - ocelot has no upper bound
+ *  - opentracker has an upper bound of 64
+ *  - udp protocol has an upper bound of 74
+ *  - xbtt has no upper bound
+ *
+ * This is only an upper bound: if the tracker complains about
+ * length, announcer will incrementally lower the batch size.
+ */
+auto inline constexpr TR_MULTISCRAPE_MAX = 60;
 
-typedef struct
+struct tr_scrape_request
 {
     /* the scrape URL */
     char const* url;
@@ -48,7 +45,7 @@ typedef struct
 
     /* how many hashes to use in the info_hash field */
     int info_hash_count;
-} tr_scrape_request;
+};
 
 struct tr_scrape_response_row
 {
@@ -95,7 +92,7 @@ struct tr_scrape_response
     int min_request_interval;
 };
 
-typedef void (*tr_scrape_response_func)(tr_scrape_response const* response, void* user_data);
+using tr_scrape_response_func = void (*)(tr_scrape_response const* response, void* user_data);
 
 void tr_tracker_http_scrape(
     tr_session* session,
@@ -113,7 +110,7 @@ void tr_tracker_udp_scrape(
 ****  ANNOUNCE
 ***/
 
-typedef enum
+enum tr_announce_event
 {
     /* Note: the ordering of this enum's values is important to
      * announcer.c's tr_tier.announce_event_priority. If changing
@@ -122,11 +119,11 @@ typedef enum
     TR_ANNOUNCE_EVENT_STARTED,
     TR_ANNOUNCE_EVENT_COMPLETED,
     TR_ANNOUNCE_EVENT_STOPPED,
-} tr_announce_event;
+};
 
 char const* tr_announce_event_get_string(tr_announce_event);
 
-typedef struct
+struct tr_announce_request
 {
     tr_announce_event event;
     bool partial_seed;
@@ -168,11 +165,11 @@ typedef struct
 
     /* the name to use when deep logging is enabled */
     char log_name[128];
-} tr_announce_request;
+};
 
 struct tr_pex;
 
-typedef struct
+struct tr_announce_response
 {
     /* the torrent's info hash */
     uint8_t info_hash[SHA_DIGEST_LENGTH];
@@ -221,9 +218,9 @@ typedef struct
     /* key generated by and returned from an http tracker.
      * if this is provided, subsequent http announces must include this. */
     char* tracker_id_str;
-} tr_announce_response;
+};
 
-typedef void (*tr_announce_response_func)(tr_announce_response const* response, void* userdata);
+using tr_announce_response_func = void (*)(tr_announce_response const* response, void* userdata);
 
 void tr_tracker_http_announce(
     tr_session* session,
diff --git a/libtransmission/announcer-udp.cc b/libtransmission/announcer-udp.cc
index bd02ff867..e08fcee54 100644
--- a/libtransmission/announcer-udp.cc
+++ b/libtransmission/announcer-udp.cc
@@ -95,14 +95,14 @@ static uint64_t evbuffer_read_ntoh_64(struct evbuffer* buf)
 *****
 ****/
 
-typedef uint64_t tau_connection_t;
+using tau_connection_t = uint64_t;
 
 enum
 {
     TAU_CONNECTION_TTL_SECS = 60
 };
 
-typedef uint32_t tau_transaction_t;
+using tau_transaction_t = uint32_t;
 
 static tau_transaction_t tau_transaction_new(void)
 {
@@ -112,13 +112,13 @@ static tau_transaction_t tau_transaction_new(void)
 }
 
 /* used in the "action" field of a request */
-typedef enum
+enum tau_action_t
 {
     TAU_ACTION_CONNECT = 0,
     TAU_ACTION_ANNOUNCE = 1,
     TAU_ACTION_SCRAPE = 2,
     TAU_ACTION_ERROR = 3
-} tau_action_t;
+};
 
 static bool is_tau_response_message(tau_action_t action, size_t msglen)
 {
@@ -295,14 +295,14 @@ struct tau_announce_request
     void* user_data;
 };
 
-typedef enum
+enum tau_announce_event
 {
     /* used in the "event" field of an announce request */
     TAU_ANNOUNCE_EVENT_NONE = 0,
     TAU_ANNOUNCE_EVENT_COMPLETED = 1,
     TAU_ANNOUNCE_EVENT_STARTED = 2,
     TAU_ANNOUNCE_EVENT_STOPPED = 3
-} tau_announce_event;
+};
 
 static tau_announce_event get_tau_announce_event(tr_announce_event e)
 {
diff --git a/libtransmission/announcer.cc b/libtransmission/announcer.cc
index 3c98b6704..5f56e3e6f 100644
--- a/libtransmission/announcer.cc
+++ b/libtransmission/announcer.cc
@@ -145,7 +145,7 @@ struct tr_scrape_info
 /**
  * "global" (per-tr_session) fields
  */
-typedef struct tr_announcer
+struct tr_announcer
 {
     std::set<tr_announce_request*, StopsCompare> stops;
     std::map<std::string, tr_scrape_info> scrape_info;
@@ -154,7 +154,7 @@ typedef struct tr_announcer
     struct event* upkeepTimer;
     int key;
     time_t tauUpkeepAt;
-} tr_announcer;
+};
 
 static struct tr_scrape_info* tr_announcerGetScrapeInfo(struct tr_announcer* announcer, std::string const& url)
 {
@@ -207,7 +207,7 @@ void tr_announcerClose(tr_session* session)
 ***/
 
 /* a row in tr_tier's list of trackers */
-typedef struct
+struct tr_tracker
 {
     char* key;
     char* announce;
@@ -223,7 +223,7 @@ typedef struct
     int consecutiveFailures;
 
     uint32_t id;
-} tr_tracker;
+};
 
 /* format: host+':'+ port */
 static char* getKey(char const* url)
@@ -267,7 +267,7 @@ static void trackerDestruct(tr_tracker* tracker)
 struct tr_torrent_tiers;
 
 /** @brief A group of trackers in a single tier, as per the multitracker spec */
-typedef struct tr_tier
+struct tr_tier
 {
     /* number of up/down/corrupt bytes since the last time we sent an
      * "event=stopped" message that was acknowledged by the tracker */
@@ -314,7 +314,7 @@ typedef struct tr_tier
 
     char lastAnnounceStr[128];
     char lastScrapeStr[128];
-} tr_tier;
+};
 
 static time_t get_next_scrape_time(tr_session const* session, tr_tier const* tier, int interval)
 {
@@ -398,7 +398,7 @@ static void tierIncrementTracker(tr_tier* tier)
  *
  * this opaque data structure can be found in tr_torrent.tiers
  */
-typedef struct tr_torrent_tiers
+struct tr_torrent_tiers
 {
     tr_tier* tiers;
     int tier_count;
@@ -408,7 +408,7 @@ typedef struct tr_torrent_tiers
 
     tr_tracker_callback callback;
     void* callbackData;
-} tr_torrent_tiers;
+};
 
 static tr_torrent_tiers* tiersNew(void)
 {
diff --git a/libtransmission/announcer.h b/libtransmission/announcer.h
index a86aada49..1fd0af856 100644
--- a/libtransmission/announcer.h
+++ b/libtransmission/announcer.h
@@ -21,19 +21,19 @@ struct tr_torrent_tiers;
  * ***  Tracker Publish / Subscribe
  * **/
 
-typedef enum
+enum TrackerEventType
 {
     TR_TRACKER_WARNING,
     TR_TRACKER_ERROR,
     TR_TRACKER_ERROR_CLEAR,
     TR_TRACKER_PEERS,
     TR_TRACKER_COUNTS,
-} TrackerEventType;
+};
 
 struct tr_pex;
 
 /** @brief Notification object to tell listeners about announce or scrape occurences */
-typedef struct
+struct tr_tracker_event
 {
     /* what type of event this is */
     TrackerEventType messageType;
@@ -49,9 +49,9 @@ typedef struct
     /* for TR_TRACKER_PEERS and TR_TRACKER_COUNTS */
     int leechers;
     int seeders;
-} tr_tracker_event;
+};
 
-typedef void (*tr_tracker_callback)(tr_torrent* tor, tr_tracker_event const* event, void* client_data);
+using tr_tracker_callback = void (*)(tr_torrent* tor, tr_tracker_event const* event, void* client_data);
 
 /**
 ***  Session ctor/dtor
diff --git a/libtransmission/bandwidth.h b/libtransmission/bandwidth.h
index 96c45647f..7ed03bfaa 100644
--- a/libtransmission/bandwidth.h
+++ b/libtransmission/bandwidth.h
@@ -100,7 +100,7 @@ struct tr_band
  *   and call tr_bandwidthClamp() before performing I/O to see how much
  *   bandwidth they can safely use.
  */
-typedef struct tr_bandwidth
+struct tr_bandwidth
 {
     /* these are PRIVATE IMPLEMENTATION details that should not be touched.
      * it's included in the header for inlining and composition. */
@@ -112,7 +112,7 @@ typedef struct tr_bandwidth
     unsigned int uniqueKey;
     tr_ptrArray children; /* struct tr_bandwidth */
     struct tr_peerIo* peer;
-} tr_bandwidth;
+};
 
 /**
 ***
diff --git a/libtransmission/bitfield.h b/libtransmission/bitfield.h
index 56d33322d..c8a18d1b9 100644
--- a/libtransmission/bitfield.h
+++ b/libtransmission/bitfield.h
@@ -16,20 +16,20 @@
 #include "tr-macros.h"
 
 /** @brief Implementation of the BitTorrent spec's Bitfield array of bits */
-typedef struct tr_bitfield
+struct tr_bitfield
 {
-    uint8_t* bits;
-    size_t alloc_count;
+    uint8_t* bits = nullptr;
+    size_t alloc_count = 0;
 
-    size_t bit_count;
+    size_t bit_count = 0;
 
-    size_t true_count;
+    size_t true_count = 0;
 
     /* Special cases for when full or empty but we don't know the bitCount.
        This occurs when a magnet link's peers send have all / have none */
-    bool have_all_hint;
-    bool have_none_hint;
-} tr_bitfield;
+    bool have_all_hint = false;
+    bool have_none_hint = false;
+};
 
 /***
 ****
diff --git a/libtransmission/blocklist.h b/libtransmission/blocklist.h
index e5ca42976..eb50014ab 100644
--- a/libtransmission/blocklist.h
+++ b/libtransmission/blocklist.h
@@ -16,7 +16,7 @@
 
 struct tr_address;
 
-typedef struct tr_blocklistFile tr_blocklistFile;
+struct tr_blocklistFile;
 
 tr_blocklistFile* tr_blocklistFileNew(char const* filename, bool isEnabled);
 
diff --git a/libtransmission/cache.h b/libtransmission/cache.h
index aaa52d33e..14cc45f91 100644
--- a/libtransmission/cache.h
+++ b/libtransmission/cache.h
@@ -15,8 +15,7 @@
 #include "tr-macros.h"
 
 struct evbuffer;
-
-typedef struct tr_cache tr_cache;
+struct tr_cache;
 
 /***
 ****
diff --git a/libtransmission/completion.h b/libtransmission/completion.h
index d2161af63..1e6bba008 100644
--- a/libtransmission/completion.h
+++ b/libtransmission/completion.h
@@ -16,7 +16,7 @@
 #include "bitfield.h"
 #include "utils.h" /* tr_getRatio() */
 
-typedef struct tr_completion
+struct tr_completion
 {
     tr_torrent* tor;
 
@@ -40,7 +40,7 @@ typedef struct tr_completion
 
     /* number of bytes we want or have now. [0..sizeWhenDone] */
     uint64_t sizeNow;
-} tr_completion;
+};
 
 /**
 *** Life Cycle
diff --git a/libtransmission/crypto-utils-polarssl.cc b/libtransmission/crypto-utils-polarssl.cc
index 03e3a84ea..06d7b2aaf 100644
--- a/libtransmission/crypto-utils-polarssl.cc
+++ b/libtransmission/crypto-utils-polarssl.cc
@@ -40,9 +40,9 @@
 
 #define MY_NAME "tr_crypto_utils"
 
-typedef API(ctr_drbg_context) api_ctr_drbg_context;
-typedef API(sha1_context) api_sha1_context;
-typedef API(dhm_context) api_dhm_context;
+using api_ctr_drbg_context = API(ctr_drbg_context);
+using api_sha1_context = API(sha1_context);
+using api_dhm_context = API(dhm_context);
 
 static void log_polarssl_error(int error_code, char const* file, int line)
 {
diff --git a/libtransmission/crypto-utils.h b/libtransmission/crypto-utils.h
index 0227050cb..4ac6cbf69 100644
--- a/libtransmission/crypto-utils.h
+++ b/libtransmission/crypto-utils.h
@@ -22,17 +22,17 @@
 **/
 
 /** @brief Opaque SHA1 context type. */
-typedef void* tr_sha1_ctx_t;
+using tr_sha1_ctx_t = void*;
 /** @brief Opaque DH context type. */
-typedef void* tr_dh_ctx_t;
+using tr_dh_ctx_t = void*;
 /** @brief Opaque DH secret key type. */
-typedef void* tr_dh_secret_t;
+using tr_dh_secret_t = void*;
 /** @brief Opaque SSL context type. */
-typedef void* tr_ssl_ctx_t;
+using tr_ssl_ctx_t = void*;
 /** @brief Opaque X509 certificate store type. */
-typedef void* tr_x509_store_t;
+using tr_x509_store_t = void*;
 /** @brief Opaque X509 certificate type. */
-typedef void* tr_x509_cert_t;
+using tr_x509_cert_t = void*;
 
 /**
  * @brief Generate a SHA1 hash from one or more chunks of memory.
diff --git a/libtransmission/crypto.h b/libtransmission/crypto.h
index 6bd2f2ab8..9618876d7 100644
--- a/libtransmission/crypto.h
+++ b/libtransmission/crypto.h
@@ -31,7 +31,7 @@ enum
 };
 
 /** @brief Holds state information for encrypted peer communications */
-typedef struct
+struct tr_crypto
 {
     struct arc4_context* dec_key;
     struct arc4_context* enc_key;
@@ -41,7 +41,7 @@ typedef struct
     uint8_t torrentHash[SHA_DIGEST_LENGTH];
     bool isIncoming;
     bool torrentHashIsSet;
-} tr_crypto;
+};
 
 /** @brief construct a new tr_crypto object */
 void tr_cryptoConstruct(tr_crypto* crypto, uint8_t const* torrentHash, bool isIncoming);
diff --git a/libtransmission/error.h b/libtransmission/error.h
index 6fb559998..e5247250b 100644
--- a/libtransmission/error.h
+++ b/libtransmission/error.h
@@ -18,13 +18,13 @@
  */
 
 /** @brief Structure holding error information. */
-typedef struct tr_error
+struct tr_error
 {
     /** @brief Error code, platform-specific */
     int code;
     /** @brief Error message */
     char* message;
-} tr_error;
+};
 
 /**
  * @brief Create new error object using literal error message.
diff --git a/libtransmission/file.h b/libtransmission/file.h
index 5ef514acc..ffc14493a 100644
--- a/libtransmission/file.h
+++ b/libtransmission/file.h
@@ -27,11 +27,11 @@ struct tr_error;
 #ifndef _WIN32
 
 /** @brief Platform-specific file descriptor type. */
-typedef int tr_sys_file_t;
+using tr_sys_file_t = int;
 /** @brief Platform-specific invalid file descriptor constant. */
 #define TR_BAD_SYS_FILE (-1)
 /** @brief Platform-specific directory descriptor type. */
-typedef void* tr_sys_dir_t;
+using tr_sys_dir_t = void*;
 /** @brief Platform-specific end-of-line sequence. */
 #define TR_NATIVE_EOL_STR "\n"
 /** @brief Platform-specific end-of-line sequence length. */
@@ -39,9 +39,10 @@ typedef void* tr_sys_dir_t;
 
 #else
 
-typedef HANDLE tr_sys_file_t;
+using tr_sys_file_t = HANDLE;
 #define TR_BAD_SYS_FILE INVALID_HANDLE_VALUE
-typedef struct tr_sys_dir_win32* tr_sys_dir_t;
+struct tr_sys_dir_win32;
+using tr_sys_dir_t = tr_sys_dir_win32*;
 #define TR_NATIVE_EOL_STR "\r\n"
 #define TR_NATIVE_EOL_STR_SIZE 2
 
@@ -50,14 +51,14 @@ typedef struct tr_sys_dir_win32* tr_sys_dir_t;
 /** @brief Platform-specific invalid directory descriptor constant. */
 #define TR_BAD_SYS_DIR ((tr_sys_dir_t) nullptr)
 
-typedef enum
+enum tr_std_sys_file_t
 {
     TR_STD_SYS_FILE_IN,
     TR_STD_SYS_FILE_OUT,
     TR_STD_SYS_FILE_ERR
-} tr_std_sys_file_t;
+};
 
-typedef enum
+enum tr_sys_file_open_flags_t
 {
     TR_SYS_FILE_READ = (1 << 0),
     TR_SYS_FILE_WRITE = (1 << 1),
@@ -66,57 +67,57 @@ typedef enum
     TR_SYS_FILE_APPEND = (1 << 4),
     TR_SYS_FILE_TRUNCATE = (1 << 5),
     TR_SYS_FILE_SEQUENTIAL = (1 << 6)
-} tr_sys_file_open_flags_t;
+};
 
-typedef enum
+enum tr_seek_origin_t
 {
     TR_SEEK_SET,
     TR_SEEK_CUR,
     TR_SEEK_END
-} tr_seek_origin_t;
+};
 
-typedef enum
+enum tr_sys_file_lock_flags_t
 {
     TR_SYS_FILE_LOCK_SH = (1 << 0),
     TR_SYS_FILE_LOCK_EX = (1 << 1),
     TR_SYS_FILE_LOCK_NB = (1 << 2),
     TR_SYS_FILE_LOCK_UN = (1 << 3)
-} tr_sys_file_lock_flags_t;
+};
 
-typedef enum
+enum tr_sys_path_get_info_flags_t
 {
     TR_SYS_PATH_NO_FOLLOW = (1 << 0)
-} tr_sys_path_get_info_flags_t;
+};
 
-typedef enum
+enum tr_sys_file_advice_t
 {
     TR_SYS_FILE_ADVICE_WILL_NEED,
     TR_SYS_FILE_ADVICE_DONT_NEED
-} tr_sys_file_advice_t;
+};
 
-typedef enum
+enum tr_sys_file_preallocate_flags_t
 {
     TR_SYS_FILE_PREALLOC_SPARSE = (1 << 0)
-} tr_sys_file_preallocate_flags_t;
+};
 
-typedef enum
+enum tr_sys_dir_create_flags_t
 {
     TR_SYS_DIR_CREATE_PARENTS = (1 << 0)
-} tr_sys_dir_create_flags_t;
+};
 
-typedef enum
+enum tr_sys_path_type_t
 {
     TR_SYS_PATH_IS_FILE,
     TR_SYS_PATH_IS_DIRECTORY,
     TR_SYS_PATH_IS_OTHER
-} tr_sys_path_type_t;
+};
 
-typedef struct tr_sys_path_info
+struct tr_sys_path_info
 {
-    tr_sys_path_type_t type;
-    uint64_t size;
-    time_t last_modified_at;
-} tr_sys_path_info;
+    tr_sys_path_type_t type = {};
+    uint64_t size = 0;
+    time_t last_modified_at = 0;
+};
 
 /**
  * @name Platform-specific wrapper functions
diff --git a/libtransmission/handshake.cc b/libtransmission/handshake.cc
index 865fefdaa..7f146600e 100644
--- a/libtransmission/handshake.cc
+++ b/libtransmission/handshake.cc
@@ -85,7 +85,7 @@ enum
 ***
 **/
 
-typedef enum
+enum handshake_state_t
 {
     /* incoming */
     AWAITING_HANDSHAKE,
@@ -103,7 +103,7 @@ typedef enum
     AWAITING_PAD_D,
     /* */
     N_STATES
-} handshake_state_t;
+};
 
 struct tr_handshake
 {
@@ -211,13 +211,13 @@ static bool buildHandshakeMessage(tr_handshake* handshake, uint8_t* buf)
 
 static ReadState tr_handshakeDone(tr_handshake* handshake, bool isConnected);
 
-typedef enum
+enum handshake_parse_err_t
 {
     HANDSHAKE_OK,
     HANDSHAKE_ENCRYPTION_WRONG,
     HANDSHAKE_BAD_TORRENT,
     HANDSHAKE_PEER_IS_SELF,
-} handshake_parse_err_t;
+};
 
 static handshake_parse_err_t parseHandshake(tr_handshake* handshake, struct evbuffer* inbuf)
 {
diff --git a/libtransmission/handshake.h b/libtransmission/handshake.h
index b6ae1f130..f1f2ab26d 100644
--- a/libtransmission/handshake.h
+++ b/libtransmission/handshake.h
@@ -22,10 +22,10 @@ struct tr_peerIo;
 
 /** @brief opaque struct holding hanshake state information.
            freed when the handshake is completed. */
-typedef struct tr_handshake tr_handshake;
+struct tr_handshake;
 
 /* returns true on success, false on error */
-typedef bool (*handshakeDoneCB)(
+using handshakeDoneCB = bool (*)(
     struct tr_handshake* handshake,
     struct tr_peerIo* io,
     bool readAnythingFromPeer,
diff --git a/libtransmission/history.h b/libtransmission/history.h
index 20c23d436..12f35c0f6 100644
--- a/libtransmission/history.h
+++ b/libtransmission/history.h
@@ -29,7 +29,7 @@ enum
     TR_RECENT_HISTORY_PERIOD_SEC = 60
 };
 
-typedef struct tr_recentHistory
+struct tr_recentHistory
 {
     /* these are PRIVATE IMPLEMENTATION details included for composition only.
      * Don't access these directly! */
@@ -41,7 +41,7 @@ typedef struct tr_recentHistory
         unsigned int n;
         time_t date;
     } slices[TR_RECENT_HISTORY_PERIOD_SEC];
-} tr_recentHistory;
+};
 
 /**
  * @brief add a counter to the recent history object.
diff --git a/libtransmission/magnet.h b/libtransmission/magnet.h
index c9d5a4439..085e656a3 100644
--- a/libtransmission/magnet.h
+++ b/libtransmission/magnet.h
@@ -16,7 +16,7 @@
 #include "transmission.h"
 #include "variant.h"
 
-typedef struct tr_magnet_info
+struct tr_magnet_info
 {
     uint8_t hash[20];
 
@@ -27,7 +27,7 @@ typedef struct tr_magnet_info
 
     int webseedCount;
     char** webseeds;
-} tr_magnet_info;
+};
 
 tr_magnet_info* tr_magnetParse(char const* uri);
 
diff --git a/libtransmission/makemeta.h b/libtransmission/makemeta.h
index 51c0731b0..e3c42b8b7 100644
--- a/libtransmission/makemeta.h
+++ b/libtransmission/makemeta.h
@@ -11,22 +11,22 @@
 #include "tr-macros.h"
 #include "transmission.h"
 
-typedef struct tr_metainfo_builder_file
+struct tr_metainfo_builder_file
 {
     char* filename;
     uint64_t size;
-} tr_metainfo_builder_file;
+};
 
-typedef enum
+enum tr_metainfo_builder_err
 {
     TR_MAKEMETA_OK,
     TR_MAKEMETA_URL,
     TR_MAKEMETA_CANCELLED,
     TR_MAKEMETA_IO_READ, /* see builder.errfile, builder.my_errno */
     TR_MAKEMETA_IO_WRITE /* see builder.errfile, builder.my_errno */
-} tr_metainfo_builder_err;
+};
 
-typedef struct tr_metainfo_builder
+struct tr_metainfo_builder
 {
     /**
     ***  These are set by tr_makeMetaInfoBuilderCreate()
@@ -78,7 +78,7 @@ typedef struct tr_metainfo_builder
     **/
 
     struct tr_metainfo_builder* nextBuilder;
-} tr_metainfo_builder;
+};
 
 tr_metainfo_builder* tr_metaInfoBuilderCreate(char const* topFile);
 
diff --git a/libtransmission/natpmp.cc b/libtransmission/natpmp.cc
index e310c9f75..42c0ed633 100644
--- a/libtransmission/natpmp.cc
+++ b/libtransmission/natpmp.cc
@@ -30,7 +30,7 @@ static char const* getKey(void)
     return _("Port Forwarding (NAT-PMP)");
 }
 
-typedef enum
+enum tr_natpmp_state
 {
     TR_NATPMP_IDLE,
     TR_NATPMP_ERR,
@@ -40,7 +40,7 @@ typedef enum
     TR_NATPMP_RECV_MAP,
     TR_NATPMP_SEND_UNMAP,
     TR_NATPMP_RECV_UNMAP
-} tr_natpmp_state;
+};
 
 struct tr_natpmp
 {
diff --git a/libtransmission/natpmp_local.h b/libtransmission/natpmp_local.h
index 2dc970423..beaef54c9 100644
--- a/libtransmission/natpmp_local.h
+++ b/libtransmission/natpmp_local.h
@@ -17,7 +17,7 @@
  * @{
  */
 
-typedef struct tr_natpmp tr_natpmp;
+struct tr_natpmp;
 
 tr_natpmp* tr_natpmpInit(void);
 
diff --git a/libtransmission/net.h b/libtransmission/net.h
index ecaba4311..422da16a9 100644
--- a/libtransmission/net.h
+++ b/libtransmission/net.h
@@ -38,7 +38,7 @@
 #include "tr-macros.h"
 
 #ifdef _WIN32
-typedef SOCKET tr_socket_t;
+using tr_socket_t = SOCKET;
 #define TR_BAD_SOCKET INVALID_SOCKET
 
 #undef EADDRINUSE
@@ -63,7 +63,7 @@ typedef SOCKET tr_socket_t;
 #define sockerrno WSAGetLastError()
 #else
 /** @brief Platform-specific socket descriptor type. */
-typedef int tr_socket_t;
+using tr_socket_t = int;
 /** @brief Platform-specific invalid socket descriptor constant. */
 #define TR_BAD_SOCKET (-1)
 
@@ -76,14 +76,14 @@ typedef int tr_socket_t;
 *****
 ****/
 
-typedef enum tr_address_type
+enum tr_address_type
 {
     TR_AF_INET,
     TR_AF_INET6,
     NUM_TR_AF_INET_TYPES
-} tr_address_type;
+};
 
-typedef struct tr_address
+struct tr_address
 {
     tr_address_type type;
     union
@@ -91,7 +91,7 @@ typedef struct tr_address
         struct in6_addr addr6;
         struct in_addr addr4;
     } addr;
-} tr_address;
+};
 
 extern tr_address const tr_inaddr_any;
 extern tr_address const tr_in6addr_any;
diff --git a/libtransmission/peer-common.h b/libtransmission/peer-common.h
index 266b8eb5b..f3de52c78 100644
--- a/libtransmission/peer-common.h
+++ b/libtransmission/peer-common.h
@@ -37,7 +37,7 @@ enum
 ***  Peer Publish / Subscribe
 **/
 
-typedef enum
+enum PeerEventType
 {
     TR_PEER_CLIENT_GOT_BLOCK,
     TR_PEER_CLIENT_GOT_CHOKE,
@@ -52,9 +52,9 @@ typedef enum
     TR_PEER_CLIENT_GOT_HAVE_NONE,
     TR_PEER_PEER_GOT_PIECE_DATA,
     TR_PEER_ERROR
-} PeerEventType;
+};
 
-typedef struct
+struct tr_peer_event
 {
     PeerEventType eventType;
 
@@ -64,17 +64,18 @@ typedef struct
     uint32_t length; /* for GOT_BLOCK + GOT_PIECE_DATA */
     int err; /* errno for GOT_ERROR */
     tr_port port; /* for GOT_PORT */
-} tr_peer_event;
+};
 
-typedef void (*tr_peer_callback)(struct tr_peer* peer, tr_peer_event const* event, void* client_data);
+using tr_peer_callback = void (*)(struct tr_peer* peer, tr_peer_event const* event, void* client_data);
 
 /***
 ****
 ***/
 
-typedef void (*tr_peer_destruct_func)(struct tr_peer* peer);
-typedef bool (
-    *tr_peer_is_transferring_pieces_func)(struct tr_peer const* peer, uint64_t now, tr_direction direction, unsigned int* Bps);
+using tr_peer_destruct_func = void (*)(struct tr_peer* peer);
+
+using tr_peer_is_transferring_pieces_func =
+    bool (*)(tr_peer const* peer, uint64_t now, tr_direction direction, unsigned int* Bps);
 
 struct tr_peer_virtual_funcs
 {
@@ -88,7 +89,7 @@ struct tr_peer_virtual_funcs
  * @see struct peer_atom
  * @see tr_peerMsgs
  */
-typedef struct tr_peer
+struct tr_peer
 {
     /* whether or not we should free this peer soon.
        NOTE: private to peer-mgr.c */
@@ -125,7 +126,7 @@ typedef struct tr_peer
     tr_recentHistory cancelsSentToPeer;
 
     struct tr_peer_virtual_funcs const* funcs;
-} tr_peer;
+};
 
 void tr_peerConstruct(struct tr_peer* peer, tr_torrent const* tor);
 
@@ -140,13 +141,13 @@ bool tr_peerIsSeed(struct tr_peer const* peer);
 ****
 ***/
 
-typedef struct tr_swarm_stats
+struct tr_swarm_stats
 {
     int activePeerCount[2];
     int activeWebseedCount;
     int peerCount;
     int peerFromCount[TR_PEER_FROM__MAX];
-} tr_swarm_stats;
+};
 
 void tr_swarmGetStats(struct tr_swarm const* swarm, tr_swarm_stats* setme);
 
diff --git a/libtransmission/peer-io.h b/libtransmission/peer-io.h
index fc58def0e..d5326de29 100644
--- a/libtransmission/peer-io.h
+++ b/libtransmission/peer-io.h
@@ -35,27 +35,27 @@ struct tr_peerIo;
  * @{
  */
 
-typedef enum
+enum ReadState
 {
     READ_NOW,
     READ_LATER,
     READ_ERR
-} ReadState;
+};
 
-typedef enum
+enum tr_encryption_type
 {
     /* these match the values in MSE's crypto_select */
     PEER_ENCRYPTION_NONE = (1 << 0),
     PEER_ENCRYPTION_RC4 = (1 << 1)
-} tr_encryption_type;
+};
 
-typedef ReadState (*tr_can_read_cb)(struct tr_peerIo* io, void* user_data, size_t* setme_piece_byte_count);
+using tr_can_read_cb = ReadState (*)(struct tr_peerIo* io, void* user_data, size_t* setme_piece_byte_count);
 
-typedef void (*tr_did_write_cb)(struct tr_peerIo* io, size_t bytesWritten, bool wasPieceData, void* userData);
+using tr_did_write_cb = void (*)(struct tr_peerIo* io, size_t bytesWritten, bool wasPieceData, void* userData);
 
-typedef void (*tr_net_error_cb)(struct tr_peerIo* io, short what, void* userData);
+using tr_net_error_cb = void (*)(struct tr_peerIo* io, short what, void* userData);
 
-typedef struct tr_peerIo
+struct tr_peerIo
 {
     bool isEncrypted;
     bool isIncoming;
@@ -100,7 +100,7 @@ typedef struct tr_peerIo
 
     struct event* event_read;
     struct event* event_write;
-} tr_peerIo;
+};
 
 /**
 ***
diff --git a/libtransmission/peer-mgr.cc b/libtransmission/peer-mgr.cc
index 29967560c..2ea5f52b9 100644
--- a/libtransmission/peer-mgr.cc
+++ b/libtransmission/peer-mgr.cc
@@ -163,7 +163,7 @@ enum piece_sort_state
 };
 
 /** @brief Opaque, per-torrent data structure for peer connection information */
-typedef struct tr_swarm
+struct tr_swarm
 {
     tr_swarm_stats stats;
 
@@ -207,7 +207,7 @@ typedef struct tr_swarm
      * requests are considered 'fast' are allowed to request a block that's
      * already been requested from another (slower?) peer. */
     int endgame;
-} tr_swarm;
+};
 
 struct tr_peerMgr
 {
@@ -2928,12 +2928,12 @@ static bool isPeerInteresting(tr_torrent* const tor, bool const* const piece_is_
     return false;
 }
 
-typedef enum
+enum tr_rechoke_state
 {
     RECHOKE_STATE_GOOD,
     RECHOKE_STATE_UNTESTED,
     RECHOKE_STATE_BAD
-} tr_rechoke_state;
+};
 
 struct tr_rechoke_info
 {
diff --git a/libtransmission/peer-mgr.h b/libtransmission/peer-mgr.h
index 00bffaabc..73d3ad284 100644
--- a/libtransmission/peer-mgr.h
+++ b/libtransmission/peer-mgr.h
@@ -29,9 +29,9 @@
  */
 
 struct UTPSocket;
+struct tr_peerMgr;
 struct tr_peer_stat;
 struct tr_torrent;
-typedef struct tr_peerMgr tr_peerMgr;
 
 /* added_f's bitwise-or'ed flags */
 enum
@@ -49,12 +49,12 @@ enum
     ADDED_F_CONNECTABLE = 16
 };
 
-typedef struct tr_pex
+struct tr_pex
 {
     tr_address addr;
     tr_port port; /* this field is in network byte order */
     uint8_t flags;
-} tr_pex;
+};
 
 struct peer_atom;
 struct tr_peerIo;
diff --git a/libtransmission/peer-msgs.cc b/libtransmission/peer-msgs.cc
index b9d5e7c77..163f6ee17 100644
--- a/libtransmission/peer-msgs.cc
+++ b/libtransmission/peer-msgs.cc
@@ -111,12 +111,12 @@ enum
     AWAITING_BT_PIECE
 };
 
-typedef enum
+enum encryption_preference_t
 {
     ENCRYPTION_PREFERENCE_UNKNOWN,
     ENCRYPTION_PREFERENCE_YES,
     ENCRYPTION_PREFERENCE_NO
-} encryption_preference_t;
+};
 
 /**
 ***
@@ -2261,7 +2261,7 @@ static void tellPeerWhatWeHave(tr_peerMsgs* msgs)
 #define MAX_PEX_ADDED 50
 #define MAX_PEX_DROPPED 50
 
-typedef struct
+struct PexDiffs
 {
     tr_pex* added;
     tr_pex* dropped;
@@ -2269,7 +2269,7 @@ typedef struct
     int addedCount;
     int droppedCount;
     int elementCount;
-} PexDiffs;
+};
 
 static void pexAddedCb(void const* vpex, void* userData)
 {
@@ -2302,7 +2302,7 @@ static inline void pexElementCb(void const* vpex, void* userData)
     diffs->elements[diffs->elementCount++] = *pex;
 }
 
-typedef void (*tr_set_func)(void const* element, void* userData);
+using tr_set_func = void (*)(void const* element, void* userData);
 
 /**
  * @brief find the differences and commonalities in two sorted sets
diff --git a/libtransmission/peer-msgs.h b/libtransmission/peer-msgs.h
index d0516e915..57245f203 100644
--- a/libtransmission/peer-msgs.h
+++ b/libtransmission/peer-msgs.h
@@ -26,7 +26,7 @@ struct tr_torrent;
  * @{
  */
 
-typedef struct tr_peerMsgs tr_peerMsgs;
+struct tr_peerMsgs;
 
 #define PEER_MSGS(o) (tr_peerMsgsCast(o))
 
diff --git a/libtransmission/platform.cc b/libtransmission/platform.cc
index 6533324f8..7a3e75791 100644
--- a/libtransmission/platform.cc
+++ b/libtransmission/platform.cc
@@ -51,9 +51,9 @@
 ***/
 
 #ifdef _WIN32
-typedef DWORD tr_thread_id;
+using tr_thread_id = DWORD;
 #else
-typedef pthread_t tr_thread_id;
+using tr_thread_id = pthread_t;
 #endif
 
 static tr_thread_id tr_getCurrentThread(void)
diff --git a/libtransmission/platform.h b/libtransmission/platform.h
index 51d27654e..3012bbd7c 100644
--- a/libtransmission/platform.h
+++ b/libtransmission/platform.h
@@ -47,7 +47,7 @@ char* tr_getSessionIdDir(void);
  * @{
  */
 
-typedef struct tr_thread tr_thread;
+struct tr_thread;
 
 /** @brief Instantiate a new process thread */
 tr_thread* tr_threadNew(void (*func)(void*), void* arg);
@@ -60,7 +60,7 @@ bool tr_amInThread(tr_thread const* thread);
 ****
 ***/
 
-typedef struct tr_lock tr_lock;
+struct tr_lock;
 
 /** @brief Create a new thread mutex object */
 tr_lock* tr_lockNew(void);
diff --git a/libtransmission/port-forwarding.h b/libtransmission/port-forwarding.h
index 6aef55dff..5cf4c50bd 100644
--- a/libtransmission/port-forwarding.h
+++ b/libtransmission/port-forwarding.h
@@ -21,7 +21,7 @@
 
 struct tr_bindsockets;
 
-typedef struct tr_shared tr_shared;
+struct tr_shared;
 
 tr_shared* tr_sharedInit(tr_session*);
 
diff --git a/libtransmission/ptrarray.h b/libtransmission/ptrarray.h
index 59947ed37..2377ffa15 100644
--- a/libtransmission/ptrarray.h
+++ b/libtransmission/ptrarray.h
@@ -23,16 +23,16 @@
 /**
  * @brief simple pointer array that resizes itself dynamically.
  */
-typedef struct tr_ptrArray
+struct tr_ptrArray
 {
     void** items;
     int n_items;
     int n_alloc;
-} tr_ptrArray;
+};
 
-typedef tr_voidptr_compare_func PtrArrayCompareFunc;
+using PtrArrayCompareFunc = tr_voidptr_compare_func;
 
-typedef void (*PtrArrayForeachFunc)(void*);
+using PtrArrayForeachFunc = void (*)(void*);
 
 /** @brief Destructor to free a tr_ptrArray's internal memory */
 void tr_ptrArrayDestruct(tr_ptrArray*, PtrArrayForeachFunc func);
diff --git a/libtransmission/quark.h b/libtransmission/quark.h
index d7304c2e2..397c748ae 100644
--- a/libtransmission/quark.h
+++ b/libtransmission/quark.h
@@ -11,7 +11,7 @@
 #include "tr-macros.h"
 
 /* Quarks — a 2-way association between a string and a unique integer identifier */
-typedef size_t tr_quark;
+using tr_quark = size_t;
 
 /*
  * Predefined Quarks.
diff --git a/libtransmission/rpc-server.h b/libtransmission/rpc-server.h
index 496359b63..7d15c4356 100644
--- a/libtransmission/rpc-server.h
+++ b/libtransmission/rpc-server.h
@@ -14,7 +14,7 @@
 
 #include "variant.h"
 
-typedef struct tr_rpc_server tr_rpc_server;
+struct tr_rpc_server;
 
 tr_rpc_server* tr_rpcInit(tr_session* session, tr_variant* settings);
 
diff --git a/libtransmission/rpcimpl.cc b/libtransmission/rpcimpl.cc
index 8cf5ef4db..34dd84607 100644
--- a/libtransmission/rpcimpl.cc
+++ b/libtransmission/rpcimpl.cc
@@ -50,11 +50,11 @@
 #define dbgmsg(...) tr_logAddDeepNamed("RPC", __VA_ARGS__)
 #endif
 
-typedef enum
+enum tr_format
 {
     TR_FORMAT_OBJECT = 0,
     TR_FORMAT_TABLE
-} tr_format;
+};
 
 /***
 ****
@@ -2741,7 +2741,7 @@ static char const* sessionClose(
 ****
 ***/
 
-typedef char const* (*handler)(tr_session*, tr_variant*, tr_variant*, struct tr_rpc_idle_data*);
+using handler = char const* (*)(tr_session*, tr_variant*, tr_variant*, struct tr_rpc_idle_data*);
 
 static struct method
 {
diff --git a/libtransmission/rpcimpl.h b/libtransmission/rpcimpl.h
index caf152ae8..ff9043d87 100644
--- a/libtransmission/rpcimpl.h
+++ b/libtransmission/rpcimpl.h
@@ -16,7 +16,7 @@
 ****  RPC processing
 ***/
 
-typedef void (*tr_rpc_response_func)(tr_session* session, tr_variant* response, void* user_data);
+using tr_rpc_response_func = void (*)(tr_session* session, tr_variant* response, void* user_data);
 
 /* http://www.json.org/ */
 void tr_rpc_request_exec_json(
diff --git a/libtransmission/session-id.h b/libtransmission/session-id.h
index 9edf2418d..51a748dda 100644
--- a/libtransmission/session-id.h
+++ b/libtransmission/session-id.h
@@ -10,7 +10,7 @@
 
 #include "tr-macros.h"
 
-typedef struct tr_session_id* tr_session_id_t;
+using tr_session_id_t = struct tr_session_id*;
 
 /**
  * Create new session identifier object.
diff --git a/libtransmission/session.h b/libtransmission/session.h
index 39b7af3dd..e1f9a7d4b 100644
--- a/libtransmission/session.h
+++ b/libtransmission/session.h
@@ -29,19 +29,19 @@
 #include "utils.h"
 #include "variant.h"
 
-typedef enum
+enum tr_tristate_t
 {
     TR_NET_OK,
     TR_NET_ERROR,
     TR_NET_WAIT
-} tr_tristate_t;
+};
 
-typedef enum
+enum tr_auto_switch_state_t
 {
     TR_AUTO_SWITCH_UNUSED,
     TR_AUTO_SWITCH_ON,
     TR_AUTO_SWITCH_OFF,
-} tr_auto_switch_state_t;
+};
 
 enum
 {
diff --git a/libtransmission/torrent.h b/libtransmission/torrent.h
index 4630a65d7..897ba51a9 100644
--- a/libtransmission/torrent.h
+++ b/libtransmission/torrent.h
@@ -112,12 +112,12 @@ void tr_torrentSetDateDone(tr_torrent* torrent, time_t doneDate);
     torrent's content than any other mime-type. */
 char const* tr_torrentPrimaryMimeType(tr_torrent const* tor);
 
-typedef enum
+enum tr_verify_state
 {
     TR_VERIFY_NONE,
     TR_VERIFY_WAIT,
     TR_VERIFY_NOW
-} tr_verify_state;
+};
 
 void tr_torrentSetVerifyState(tr_torrent* tor, tr_verify_state state);
 
diff --git a/libtransmission/tr-getopt.h b/libtransmission/tr-getopt.h
index a6288840a..c3ce668dd 100644
--- a/libtransmission/tr-getopt.h
+++ b/libtransmission/tr-getopt.h
@@ -18,7 +18,7 @@
 /** @brief Similar to optind, this is the current index into argv */
 extern int tr_optind;
 
-typedef struct tr_option
+struct tr_option
 {
     int val; /* the value to return from tr_getopt() */
     char const* longName; /* --long-form */
@@ -26,7 +26,7 @@ typedef struct tr_option
     char const* shortName; /* short form */
     bool has_arg; /* 0 for no argument, 1 for argument */
     char const* argName; /* argument's description for tr_getopt_usage() */
-} tr_option;
+};
 
 enum
 {
diff --git a/libtransmission/tr-lpd.cc b/libtransmission/tr-lpd.cc
index e68ea3b7d..b69c96cdd 100644
--- a/libtransmission/tr-lpd.cc
+++ b/libtransmission/tr-lpd.cc
@@ -30,7 +30,7 @@ THE SOFTWARE.
 #ifdef _WIN32
 #include <inttypes.h>
 #include <ws2tcpip.h>
-typedef uint16_t in_port_t; /* all missing */
+using in_port_t = uint16_t; /* all missing */
 #else
 #include <ctime>
 #include <unistd.h> /* close() */
diff --git a/libtransmission/transmission.h b/libtransmission/transmission.h
index 5c48cb561..0cc6c53bf 100644
--- a/libtransmission/transmission.h
+++ b/libtransmission/transmission.h
@@ -27,40 +27,39 @@
 
 #include "tr-macros.h"
 
-typedef uint32_t tr_file_index_t;
-typedef uint32_t tr_piece_index_t;
+using tr_file_index_t = uint32_t;
+using tr_piece_index_t = uint32_t;
 /* assuming a 16 KiB block, a 32-bit block index gives us a maximum torrent size of 63 TiB.
  * if we ever need to grow past that, change this to uint64_t ;) */
-typedef uint32_t tr_block_index_t;
-typedef uint16_t tr_port;
-
-typedef struct tr_ctor tr_ctor;
-typedef struct tr_info tr_info;
-typedef struct tr_torrent tr_torrent;
-typedef struct tr_session tr_session;
+using tr_block_index_t = uint32_t;
+using tr_port = uint16_t;
 
+struct tr_ctor;
 struct tr_error;
+struct tr_info;
+struct tr_session;
+struct tr_torrent;
 struct tr_variant;
 
-typedef int8_t tr_priority_t;
+using tr_priority_t = int8_t;
 
-typedef int (*tr_voidptr_compare_func)(void const* lhs, void const* rhs);
+using tr_voidptr_compare_func = int (*)(void const* lhs, void const* rhs);
 
 #define TR_RPC_SESSION_ID_HEADER "X-Transmission-Session-Id"
 
-typedef enum
+enum tr_preallocation_mode
 {
     TR_PREALLOCATE_NONE = 0,
     TR_PREALLOCATE_SPARSE = 1,
     TR_PREALLOCATE_FULL = 2
-} tr_preallocation_mode;
+};
 
-typedef enum
+enum tr_encryption_mode
 {
     TR_CLEAR_PREFERRED,
     TR_ENCRYPTION_PREFERRED,
     TR_ENCRYPTION_REQUIRED
-} tr_encryption_mode;
+};
 
 /***
 ****
@@ -379,7 +378,7 @@ bool tr_sessionIsRPCPasswordEnabled(tr_session const* session);
 
 char const* tr_sessionGetRPCBindAddress(tr_session const* session);
 
-typedef enum
+enum tr_rpc_callback_type
 {
     TR_RPC_TORRENT_ADDED,
     TR_RPC_TORRENT_STARTED,
@@ -391,9 +390,9 @@ typedef enum
     TR_RPC_SESSION_CHANGED,
     TR_RPC_SESSION_QUEUE_POSITIONS_CHANGED, /* catch potentially multiple torrents being moved in the queue */
     TR_RPC_SESSION_CLOSE
-} tr_rpc_callback_type;
+};
 
-typedef enum
+enum tr_rpc_callback_status
 {
     /* no special handling is needed by the caller */
     TR_RPC_OK = 0,
@@ -402,9 +401,9 @@ typedef enum
      * need to keep the torrent alive long enough to cleanly close
      * some resources in another thread. */
     TR_RPC_NOREMOVE = (1 << 1)
-} tr_rpc_callback_status;
+};
 
-typedef tr_rpc_callback_status (*tr_rpc_func)( //
+using tr_rpc_func = tr_rpc_callback_status (*)( //
     tr_session* session,
     tr_rpc_callback_type type,
     struct tr_torrent* tor_or_null,
@@ -426,7 +425,7 @@ void tr_sessionSetRPCCallback(tr_session* session, tr_rpc_func func, void* user_
 **/
 
 /** @brief Used by tr_sessionGetStats() and tr_sessionGetCumulativeStats() */
-typedef struct tr_session_stats
+struct tr_session_stats
 {
     float ratio; /* TR_RATIO_INF, TR_RATIO_NA, or total up/down */
     uint64_t uploadedBytes; /* total up */
@@ -434,7 +433,7 @@ typedef struct tr_session_stats
     uint64_t filesAdded; /* number of files added */
     uint64_t sessionCount; /* program started N times */
     uint64_t secondsActive; /* how long Transmisson's been running */
-} tr_session_stats;
+};
 
 /** @brief Get bandwidth use statistics for the current session */
 void tr_sessionGetStats(tr_session const* session, tr_session_stats* setme);
@@ -486,24 +485,24 @@ void tr_sessionSetPeerPortRandomOnStart(tr_session* session, bool random);
 
 bool tr_sessionGetPeerPortRandomOnStart(tr_session* session);
 
-typedef enum
+enum tr_port_forwarding
 {
     TR_PORT_ERROR,
     TR_PORT_UNMAPPED,
     TR_PORT_UNMAPPING,
     TR_PORT_MAPPING,
     TR_PORT_MAPPED
-} tr_port_forwarding;
+};
 
 tr_port_forwarding tr_sessionGetPortForwarding(tr_session const* session);
 
-typedef enum
+enum tr_direction
 {
     TR_CLIENT_TO_PEER = 0,
     TR_UP = 0,
     TR_PEER_TO_CLIENT = 1,
     TR_DOWN = 1
-} tr_direction;
+};
 
 /***
 ****
@@ -538,7 +537,7 @@ int tr_sessionGetAltSpeedBegin(tr_session const*);
 void tr_sessionSetAltSpeedEnd(tr_session*, int minsSinceMidnight);
 int tr_sessionGetAltSpeedEnd(tr_session const*);
 
-typedef enum
+enum tr_sched_day
 {
     TR_SCHED_SUN = (1 << 0),
     TR_SCHED_MON = (1 << 1),
@@ -550,12 +549,12 @@ typedef enum
     TR_SCHED_WEEKDAY = (TR_SCHED_MON | TR_SCHED_TUES | TR_SCHED_WED | TR_SCHED_THURS | TR_SCHED_FRI),
     TR_SCHED_WEEKEND = (TR_SCHED_SUN | TR_SCHED_SAT),
     TR_SCHED_ALL = (TR_SCHED_WEEKDAY | TR_SCHED_WEEKEND)
-} tr_sched_day;
+};
 
 void tr_sessionSetAltSpeedDay(tr_session*, tr_sched_day day);
 tr_sched_day tr_sessionGetAltSpeedDay(tr_session const*);
 
-typedef void (*tr_altSpeedFunc)(tr_session*, bool active, bool userDriven, void*);
+using tr_altSpeedFunc = void (*)(tr_session*, bool active, bool userDriven, void*);
 
 void tr_sessionSetAltSpeedFunc(tr_session*, tr_altSpeedFunc, void*);
 
@@ -718,18 +717,18 @@ void tr_sessionSetTorrentDoneScript(tr_session*, char const* scriptFilename);
 ** Message Logging
 */
 
-typedef enum
+enum tr_log_level
 {
     TR_LOG_SILENT = 0,
     TR_LOG_ERROR = 1,
     TR_LOG_INFO = 2,
     TR_LOG_DEBUG = 3,
     TR_LOG_FIREHOSE = 4
-} tr_log_level;
+};
 
 void tr_logSetLevel(tr_log_level);
 
-typedef struct tr_log_message
+struct tr_log_message
 {
     /* TR_LOG_ERROR, TR_LOG_INFO, or TR_LOG_DEBUG */
     tr_log_level level;
@@ -753,7 +752,7 @@ typedef struct tr_log_message
 
     /* linked list of messages */
     struct tr_log_message* next;
-} tr_log_message;
+};
 
 tr_log_message* tr_logGetQueue(void);
 bool tr_logGetQueueEnabled(void);
@@ -827,11 +826,11 @@ char const* tr_blocklistGetURL(tr_session const*);
     Every call to tr_ctorSetMetainfo* () frees the previous metainfo.
  */
 
-typedef enum
+enum tr_ctorMode
 {
     TR_FALLBACK, /* indicates the ctor value should be used only in case of missing resume settings */
     TR_FORCE /* indicates the ctor value should be used regardless of what's in the resume settings */
-} tr_ctorMode;
+};
 
 /** @brief Create a torrent constructor object used to instantiate a tr_torrent
     @param session_or_NULL the tr_session.
@@ -917,12 +916,12 @@ tr_session* tr_ctorGetSession(tr_ctor const* ctor);
            or NULL if tr_ctorSetMetainfoFromFile() wasn't used */
 char const* tr_ctorGetSourceFile(tr_ctor const* ctor);
 
-typedef enum
+enum tr_parse_result
 {
     TR_PARSE_OK,
     TR_PARSE_ERR,
     TR_PARSE_DUPLICATE
-} tr_parse_result;
+};
 
 /**
  * @brief Parses the specified metainfo
@@ -974,7 +973,7 @@ tr_torrent* tr_torrentNew(tr_ctor const* ctor, int* setme_error, int* setme_dupl
 /** @addtogroup tr_torrent Torrents
     @{ */
 
-typedef bool (*tr_fileFunc)(char const* filename, struct tr_error** error);
+using tr_fileFunc = bool (*)(char const* filename, struct tr_error** error);
 
 /** @brief Removes our .torrent and .resume files for this torrent */
 void tr_torrentRemove(tr_torrent* torrent, bool removeLocalData, tr_fileFunc removeFunc);
@@ -985,7 +984,7 @@ void tr_torrentStart(tr_torrent* torrent);
 /** @brief Stop (pause) a torrent */
 void tr_torrentStop(tr_torrent* torrent);
 
-typedef void (*tr_torrent_rename_done_func)( //
+using tr_torrent_rename_done_func = void (*)( //
     tr_torrent* torrent,
     char const* oldpath,
     char const* newname,
@@ -1113,7 +1112,7 @@ bool tr_torrentUsesSessionLimits(tr_torrent const*);
 *****  Ratio Limits
 ****/
 
-typedef enum
+enum tr_ratiolimit
 {
     /* follow the global settings */
     TR_RATIOLIMIT_GLOBAL = 0,
@@ -1121,7 +1120,7 @@ typedef enum
     TR_RATIOLIMIT_SINGLE = 1,
     /* override the global settings, seeding regardless of ratio */
     TR_RATIOLIMIT_UNLIMITED = 2
-} tr_ratiolimit;
+};
 
 void tr_torrentSetRatioMode(tr_torrent* tor, tr_ratiolimit mode);
 
@@ -1137,7 +1136,7 @@ bool tr_torrentGetSeedRatio(tr_torrent const*, double* ratio);
 *****  Idle Time Limits
 ****/
 
-typedef enum
+enum tr_idlelimit
 {
     /* follow the global settings */
     TR_IDLELIMIT_GLOBAL = 0,
@@ -1145,7 +1144,7 @@ typedef enum
     TR_IDLELIMIT_SINGLE = 1,
     /* override the global settings, seeding regardless of activity */
     TR_IDLELIMIT_UNLIMITED = 2
-} tr_idlelimit;
+};
 
 void tr_torrentSetIdleMode(tr_torrent* tor, tr_idlelimit mode);
 
@@ -1233,13 +1232,13 @@ static inline char* tr_torrentGetMagnetLink(tr_torrent const* tor)
 **/
 
 /** @brief a part of tr_info that represents a single tracker */
-typedef struct tr_tracker_info
+struct tr_tracker_info
 {
     int tier;
     char* announce;
     char* scrape;
     uint32_t id; /* unique identifier used to match to a tr_tracker_stat */
-} tr_tracker_info;
+};
 
 /**
  * @brief Modify a torrent's tracker list.
@@ -1260,26 +1259,26 @@ bool tr_torrentSetAnnounceList(tr_torrent* torrent, tr_tracker_info const* track
 ***
 **/
 
-typedef enum
+enum tr_completeness
 {
     TR_LEECH, /* doesn't have all the desired pieces */
     TR_SEED, /* has the entire torrent */
     TR_PARTIAL_SEED /* has the desired pieces, but not the entire torrent */
-} tr_completeness;
+};
 
 /**
  * @param wasRunning whether or not the torrent was running when
  *                   it changed its completeness state
  */
-typedef void (*tr_torrent_completeness_func)( //
+using tr_torrent_completeness_func = void (*)( //
     tr_torrent* torrent,
     tr_completeness completeness,
     bool wasRunning,
     void* user_data);
 
-typedef void (*tr_torrent_ratio_limit_hit_func)(tr_torrent* torrent, void* user_data);
+using tr_torrent_ratio_limit_hit_func = void (*)(tr_torrent* torrent, void* user_data);
 
-typedef void (*tr_torrent_idle_limit_hit_func)(tr_torrent* torrent, void* user_data);
+using tr_torrent_idle_limit_hit_func = void (*)(tr_torrent* torrent, void* user_data);
 
 /**
  * Register to be notified whenever a torrent's "completeness"
@@ -1298,7 +1297,8 @@ void tr_torrentSetCompletenessCallback(tr_torrent* torrent, tr_torrent_completen
 
 void tr_torrentClearCompletenessCallback(tr_torrent* torrent);
 
-typedef void (*tr_torrent_metadata_func)(tr_torrent* torrent, void* user_data);
+using tr_torrent_metadata_func = void (*)(tr_torrent* torrent, void* user_data);
+
 /**
  * Register to be notified whenever a torrent changes from
  * having incomplete metadata to having complete metadata.
@@ -1350,7 +1350,7 @@ bool tr_torrentCanManualUpdate(tr_torrent const* torrent);
 ****  tr_peer_stat
 ***/
 
-typedef struct tr_peer_stat
+struct tr_peer_stat
 {
     bool isUTP;
 
@@ -1394,7 +1394,7 @@ typedef struct tr_peer_stat
 
     /* how many requests we've made and are currently awaiting a response for */
     int pendingReqsToPeer;
-} tr_peer_stat;
+};
 
 tr_peer_stat* tr_torrentPeers(tr_torrent const* torrent, int* peerCount);
 
@@ -1404,7 +1404,7 @@ void tr_torrentPeersFree(tr_peer_stat* peerStats, int peerCount);
 ****  tr_tracker_stat
 ***/
 
-typedef enum
+enum tr_tracker_state
 {
     /* we won't (announce,scrape) this torrent to this tracker because
      * the torrent is stopped, or because of an error, or whatever */
@@ -1417,9 +1417,9 @@ typedef enum
     TR_TRACKER_QUEUED = 2,
     /* we're (announcing,scraping) this torrent right now */
     TR_TRACKER_ACTIVE = 3
-} tr_tracker_state;
+};
 
-typedef struct
+struct tr_tracker_stat
 {
     /* how many downloads this tracker knows of (-1 means it does not know) */
     int downloadCount;
@@ -1510,7 +1510,7 @@ typedef struct
 
     /* used to match to a tr_tracker_info */
     uint32_t id;
-} tr_tracker_stat;
+};
 
 tr_tracker_stat* tr_torrentTrackers(tr_torrent const* torrent, int* setmeTrackerCount);
 
@@ -1528,11 +1528,11 @@ void tr_torrentTrackersFree(tr_tracker_stat* trackerStats, int trackerCount);
  */
 double* tr_torrentWebSpeeds_KBps(tr_torrent const* torrent);
 
-typedef struct tr_file_stat
+struct tr_file_stat
 {
     uint64_t bytesCompleted;
     float progress;
-} tr_file_stat;
+};
 
 tr_file_stat* tr_torrentFiles(tr_torrent const* torrent, tr_file_index_t* fileCount);
 
@@ -1559,7 +1559,7 @@ void tr_torrentAmountFinished(tr_torrent const* torrent, float* tab, int size);
  *                being called during verification.
  * @param user_data the user-defined pointer from tr_torrentVerify()
  */
-typedef void (*tr_verify_done_func)(tr_torrent* torrent, bool aborted, void* user_data);
+using tr_verify_done_func = void (*)(tr_torrent* torrent, bool aborted, void* user_data);
 
 /**
  * Queue a torrent for verification.
@@ -1575,7 +1575,7 @@ void tr_torrentVerify(tr_torrent* torrent, tr_verify_done_func callback_func_or_
  **********************************************************************/
 
 /** @brief a part of tr_info that represents a single file of the torrent's content */
-typedef struct tr_file
+struct tr_file
 {
     uint64_t length; /* Length of the file, in bytes */
     char* name; /* Path to the file */
@@ -1585,16 +1585,16 @@ typedef struct tr_file
     tr_piece_index_t firstPiece; /* We need pieces [firstPiece... */
     tr_piece_index_t lastPiece; /* ...lastPiece] to dl this file */
     uint64_t offset; /* file begins at the torrent's nth byte */
-} tr_file;
+};
 
 /** @brief a part of tr_info that represents a single piece of the torrent's content */
-typedef struct tr_piece
+struct tr_piece
 {
     time_t timeChecked; /* the last time we tested this piece */
     uint8_t hash[SHA_DIGEST_LENGTH]; /* pieces hash */
     int8_t priority; /* TR_PRI_HIGH, _NORMAL, or _LOW */
     bool dnd; /* "do not download" flag */
-} tr_piece;
+};
 
 /** @brief information about a torrent that comes from its metainfo file */
 struct tr_info
@@ -1652,7 +1652,7 @@ static inline bool tr_torrentHasMetadata(tr_torrent const* tor)
  * Note: these values will become a straight enum at some point in the future.
  * Do not rely on their current `bitfield' implementation
  */
-typedef enum
+enum tr_torrent_activity
 {
     TR_STATUS_STOPPED = 0, /* Torrent is stopped */
     TR_STATUS_CHECK_WAIT = 1, /* Queued to check files */
@@ -1661,7 +1661,7 @@ typedef enum
     TR_STATUS_DOWNLOAD = 4, /* Downloading */
     TR_STATUS_SEED_WAIT = 5, /* Queued to seed */
     TR_STATUS_SEED = 6 /* Seeding */
-} tr_torrent_activity;
+};
 
 enum
 {
@@ -1675,7 +1675,7 @@ enum
     TR_PEER_FROM__MAX
 };
 
-typedef enum
+enum tr_stat_errtype
 {
     /* everything's fine */
     TR_STAT_OK = 0,
@@ -1685,10 +1685,10 @@ typedef enum
     TR_STAT_TRACKER_ERROR = 2,
     /* local trouble, such as disk full or permissions error */
     TR_STAT_LOCAL_ERROR = 3
-} tr_stat_errtype;
+};
 
 /** @brief Used by tr_torrentStat() to tell clients about a torrent's state and statistics */
-typedef struct tr_stat
+struct tr_stat
 {
     /** The torrent's unique Id.
         @see tr_torrentId() */
@@ -1858,7 +1858,7 @@ typedef struct tr_stat
     /** True if the torrent is running, but has been idle for long enough
         to be considered stalled.  @see tr_sessionGetQueueStalledMinutes() */
     bool isStalled;
-} tr_stat;
+};
 
 /** Return a pointer to an tr_stat structure with updated information
     on the torrent. This is typically called by the GUI clients every
diff --git a/libtransmission/trevent.cc b/libtransmission/trevent.cc
index a92ad58e4..eb8c71fa7 100644
--- a/libtransmission/trevent.cc
+++ b/libtransmission/trevent.cc
@@ -33,7 +33,7 @@
 
 #ifdef _WIN32
 
-typedef SOCKET tr_pipe_end_t;
+using tr_pipe_end_t = SOCKET;
 
 static int pgpipe(tr_pipe_end_t handles[2])
 {
@@ -139,7 +139,7 @@ static int piperead(tr_pipe_end_t s, void* buf, int len)
 #define pipewrite(a, b, c) send(a, (char*)b, c, 0)
 
 #else
-typedef int tr_pipe_end_t;
+using tr_pipe_end_t = int;
 #define piperead(a, b, c) read(a, b, c)
 #define pipewrite(a, b, c) write(a, b, c)
 #endif
@@ -148,7 +148,7 @@ typedef int tr_pipe_end_t;
 ****
 ***/
 
-typedef struct tr_event_handle
+struct tr_event_handle
 {
     bool die;
     tr_pipe_end_t fds[2];
@@ -157,7 +157,7 @@ typedef struct tr_event_handle
     tr_thread* thread;
     struct event_base* base;
     struct event* pipeEvent;
-} tr_event_handle;
+};
 
 struct tr_run_data
 {
diff --git a/libtransmission/upnp.cc b/libtransmission/upnp.cc
index 06be64ff2..d0dc5770e 100644
--- a/libtransmission/upnp.cc
+++ b/libtransmission/upnp.cc
@@ -29,14 +29,14 @@ static char const* getKey(void)
     return _("Port Forwarding (UPnP)");
 }
 
-typedef enum
+enum tr_upnp_state
 {
     TR_UPNP_IDLE,
     TR_UPNP_ERR,
     TR_UPNP_DISCOVER,
     TR_UPNP_MAP,
     TR_UPNP_UNMAP
-} tr_upnp_state;
+};
 
 struct tr_upnp
 {
diff --git a/libtransmission/upnp.h b/libtransmission/upnp.h
index ffb6404a2..59f761bda 100644
--- a/libtransmission/upnp.h
+++ b/libtransmission/upnp.h
@@ -17,7 +17,7 @@
  * @{
  */
 
-typedef struct tr_upnp tr_upnp;
+struct tr_upnp;
 
 tr_upnp* tr_upnpInit(void);
 
diff --git a/libtransmission/variant-common.h b/libtransmission/variant-common.h
index 56f0194bc..3834ecb0c 100644
--- a/libtransmission/variant-common.h
+++ b/libtransmission/variant-common.h
@@ -14,7 +14,7 @@
 
 #include "tr-macros.h"
 
-typedef void (*VariantWalkFunc)(tr_variant const* val, void* user_data);
+using VariantWalkFunc = void (*)(tr_variant const* val, void* user_data);
 
 struct VariantWalkFuncs
 {
diff --git a/libtransmission/variant.h b/libtransmission/variant.h
index 75554f552..e16633848 100644
--- a/libtransmission/variant.h
+++ b/libtransmission/variant.h
@@ -29,12 +29,12 @@ struct tr_error;
  * @{
  */
 
-typedef enum
+enum tr_string_type
 {
     TR_STRING_TYPE_QUARK,
     TR_STRING_TYPE_HEAP,
     TR_STRING_TYPE_BUF
-} tr_string_type;
+};
 
 /* these are PRIVATE IMPLEMENTATION details that should not be touched.
  * I'll probably change them just to break your code! HA HA HA!
@@ -66,11 +66,11 @@ enum
 /* These are PRIVATE IMPLEMENTATION details that should not be touched.
  * I'll probably change them just to break your code! HA HA HA!
  * it's included in the header for inlining and composition */
-typedef struct tr_variant
+struct tr_variant
 {
-    char type;
+    char type = '\0';
 
-    tr_quark key;
+    tr_quark key = TR_KEY_NONE;
 
     union
     {
@@ -88,8 +88,8 @@ typedef struct tr_variant
             size_t count;
             struct tr_variant* vals;
         } l;
-    } val;
-} tr_variant;
+    } val = {};
+};
 
 void tr_variantFree(tr_variant*);
 
@@ -97,12 +97,12 @@ void tr_variantFree(tr_variant*);
 ****  Serialization / Deserialization
 ***/
 
-typedef enum
+enum tr_variant_fmt
 {
     TR_VARIANT_FMT_BENC,
     TR_VARIANT_FMT_JSON,
     TR_VARIANT_FMT_JSON_LEAN /* saves bandwidth by omitting all whitespace. */
-} tr_variant_fmt;
+};
 
 int tr_variantToFile(tr_variant const* variant, tr_variant_fmt fmt, char const* filename);
 
diff --git a/libtransmission/watchdir-common.h b/libtransmission/watchdir-common.h
index f3d807848..32ef1a39a 100644
--- a/libtransmission/watchdir-common.h
+++ b/libtransmission/watchdir-common.h
@@ -15,10 +15,10 @@
 #include <string>
 #include <unordered_set>
 
-typedef struct tr_watchdir_backend
+struct tr_watchdir_backend
 {
     void (*free_func)(struct tr_watchdir_backend*);
-} tr_watchdir_backend;
+};
 
 #define BACKEND_DOWNCAST(b) (reinterpret_cast<tr_watchdir_backend*>(b))
 
diff --git a/libtransmission/watchdir-generic.cc b/libtransmission/watchdir-generic.cc
index b51fca0e6..1e94f1a2f 100644
--- a/libtransmission/watchdir-generic.cc
+++ b/libtransmission/watchdir-generic.cc
@@ -33,13 +33,13 @@
 ****
 ***/
 
-typedef struct tr_watchdir_generic
+struct tr_watchdir_generic
 {
     tr_watchdir_backend base;
 
     struct event* event;
     std::unordered_set<std::string> dir_entries;
-} tr_watchdir_generic;
+};
 
 #define BACKEND_UPCAST(b) (reinterpret_cast<tr_watchdir_generic*>(b))
 
diff --git a/libtransmission/watchdir-inotify.cc b/libtransmission/watchdir-inotify.cc
index b675507c6..fe3a22462 100644
--- a/libtransmission/watchdir-inotify.cc
+++ b/libtransmission/watchdir-inotify.cc
@@ -38,14 +38,14 @@
 ****
 ***/
 
-typedef struct tr_watchdir_inotify
+struct tr_watchdir_inotify
 {
     tr_watchdir_backend base;
 
     int infd;
     int inwd;
     struct bufferevent* event;
-} tr_watchdir_inotify;
+};
 
 #define BACKEND_UPCAST(b) ((tr_watchdir_inotify*)(b))
 
diff --git a/libtransmission/watchdir-kqueue.cc b/libtransmission/watchdir-kqueue.cc
index 0ecc4dce3..697f8218a 100644
--- a/libtransmission/watchdir-kqueue.cc
+++ b/libtransmission/watchdir-kqueue.cc
@@ -44,7 +44,7 @@
 ****
 ***/
 
-typedef struct tr_watchdir_kqueue
+struct tr_watchdir_kqueue
 {
     tr_watchdir_backend base;
 
@@ -52,7 +52,7 @@ typedef struct tr_watchdir_kqueue
     int dirfd;
     struct event* event;
     std::unordered_set<std::string> dir_entries;
-} tr_watchdir_kqueue;
+};
 
 #define BACKEND_UPCAST(b) (reinterpret_cast<tr_watchdir_kqueue*>(b))
 
diff --git a/libtransmission/watchdir-win32.cc b/libtransmission/watchdir-win32.cc
index 79d76c4b5..ec85c08b4 100644
--- a/libtransmission/watchdir-win32.cc
+++ b/libtransmission/watchdir-win32.cc
@@ -40,7 +40,7 @@
 ****
 ***/
 
-typedef struct tr_watchdir_win32
+struct tr_watchdir_win32
 {
     tr_watchdir_backend base;
 
@@ -50,7 +50,7 @@ typedef struct tr_watchdir_win32
     evutil_socket_t notify_pipe[2];
     struct bufferevent* event;
     HANDLE thread;
-} tr_watchdir_win32;
+};
 
 #define BACKEND_UPCAST(b) ((tr_watchdir_win32*)(b))
 
@@ -67,7 +67,7 @@ static BOOL tr_get_overlapped_result_ex(
     DWORD timeout,
     BOOL alertable)
 {
-    typedef BOOL(WINAPI * impl_t)(HANDLE, LPOVERLAPPED, LPDWORD, DWORD, BOOL);
+    using impl_t = BOOL(WINAPI*)(HANDLE, LPOVERLAPPED, LPDWORD, DWORD, BOOL);
 
     static impl_t real_impl = nullptr;
     static bool is_real_impl_valid = false;
diff --git a/libtransmission/watchdir.cc b/libtransmission/watchdir.cc
index 8eb0411ad..6eaa5fdf6 100644
--- a/libtransmission/watchdir.cc
+++ b/libtransmission/watchdir.cc
@@ -113,14 +113,14 @@ static tr_watchdir_status tr_watchdir_process_impl(tr_watchdir_t handle, char co
 ****
 ***/
 
-typedef struct tr_watchdir_retry
+struct tr_watchdir_retry
 {
     tr_watchdir_t handle;
     char* name;
     size_t counter;
     struct event* timer;
     struct timeval interval;
-} tr_watchdir_retry;
+};
 
 /* Non-static and mutable for unit tests */
 auto tr_watchdir_retry_limit = size_t{ 3 };
diff --git a/libtransmission/watchdir.h b/libtransmission/watchdir.h
index b897a19a5..cd1535a94 100644
--- a/libtransmission/watchdir.h
+++ b/libtransmission/watchdir.h
@@ -12,16 +12,16 @@
 
 struct event_base;
 
-typedef struct tr_watchdir* tr_watchdir_t;
+using tr_watchdir_t = struct tr_watchdir*;
 
-typedef enum
+enum tr_watchdir_status
 {
     TR_WATCHDIR_ACCEPT,
     TR_WATCHDIR_IGNORE,
     TR_WATCHDIR_RETRY
-} tr_watchdir_status;
+};
 
-typedef tr_watchdir_status (*tr_watchdir_cb)(tr_watchdir_t handle, char const* name, void* user_data);
+using tr_watchdir_cb = tr_watchdir_status (*)(tr_watchdir_t handle, char const* name, void* user_data);
 
 /* ... */
 
diff --git a/libtransmission/web.h b/libtransmission/web.h
index 39ebdc676..e3f282cbb 100644
--- a/libtransmission/web.h
+++ b/libtransmission/web.h
@@ -13,15 +13,15 @@
 struct tr_address;
 struct tr_web_task;
 
-typedef enum
+enum tr_web_close_mode
 {
     TR_WEB_CLOSE_WHEN_IDLE,
     TR_WEB_CLOSE_NOW
-} tr_web_close_mode;
+};
 
 void tr_webClose(tr_session* session, tr_web_close_mode close_mode);
 
-typedef void (*tr_web_done_func)(
+using tr_web_done_func = void (*)(
     tr_session* session,
     bool did_connect_flag,
     bool timeout_flag,
diff --git a/libtransmission/webseed.h b/libtransmission/webseed.h
index 7be5cecda..5a289db19 100644
--- a/libtransmission/webseed.h
+++ b/libtransmission/webseed.h
@@ -12,7 +12,7 @@
 #error only libtransmission should #include this header.
 #endif
 
-typedef struct tr_webseed tr_webseed;
+struct tr_webseed;
 
 #include "peer-common.h"
 
diff --git a/qt/AddData.cc b/qt/AddData.cc
index 3f0610602..967bd5cf9 100644
--- a/qt/AddData.cc
+++ b/qt/AddData.cc
@@ -25,7 +25,7 @@ QString getNameFromMetainfo(QByteArray const& metainfo)
     tr_ctor* ctor = tr_ctorNew(nullptr);
     tr_ctorSetMetainfo(ctor, metainfo.constData(), metainfo.size());
 
-    tr_info inf;
+    auto inf = tr_info{};
     if (tr_torrentParse(ctor, &inf) == TR_PARSE_OK)
     {
         name = QString::fromUtf8(inf.name); // metainfo is required to be UTF-8
diff --git a/qt/MakeDialog.cc b/qt/MakeDialog.cc
index 62f52e7b8..3748e0c6c 100644
--- a/qt/MakeDialog.cc
+++ b/qt/MakeDialog.cc
@@ -156,7 +156,7 @@ void MakeDialog::makeTorrent()
         }
         else
         {
-            tr_tracker_info tmp;
+            auto tmp = tr_tracker_info{};
             tmp.announce = tr_strdup(announce_url.toUtf8().constData());
             tmp.tier = tier;
             trackers.append(tmp);
diff --git a/qt/WatchDir.cc b/qt/WatchDir.cc
index ba3a5e5d8..5d419a271 100644
--- a/qt/WatchDir.cc
+++ b/qt/WatchDir.cc
@@ -32,7 +32,7 @@ WatchDir::WatchDir(TorrentModel const& model)
 int WatchDir::metainfoTest(QString const& filename) const
 {
     int ret;
-    tr_info inf;
+    auto inf = tr_info{};
     tr_ctor* ctor = tr_ctorNew(nullptr);
 
     // parse
diff --git a/tests/libtransmission/crypto-test.cc b/tests/libtransmission/crypto-test.cc
index 4b242e935..c791edbe1 100644
--- a/tests/libtransmission/crypto-test.cc
+++ b/tests/libtransmission/crypto-test.cc
@@ -22,7 +22,7 @@
 
 TEST(Crypto, torrentHash)
 {
-    tr_crypto a;
+    auto a = tr_crypto{};
 
     auto hash = std::array<uint8_t, SHA_DIGEST_LENGTH>{};
     for (size_t i = 0; i < hash.size(); ++i)
diff --git a/tests/libtransmission/makemeta-test.cc b/tests/libtransmission/makemeta-test.cc
index c7a298d2d..47e92ef4e 100644
--- a/tests/libtransmission/makemeta-test.cc
+++ b/tests/libtransmission/makemeta-test.cc
@@ -37,7 +37,7 @@ protected:
         bool isPrivate)
     {
         // char* sandbox;
-        tr_info inf;
+        auto inf = tr_info{};
 
         // create a single input file
         auto input_file = makeString(tr_buildPath(sandboxDir().data(), "test.XXXXXX", nullptr));
@@ -151,7 +151,7 @@ protected:
         // now let's check our work: parse the  .torrent file
         auto* ctor = tr_ctorNew(nullptr);
         tr_ctorSetMetainfoFromFile(ctor, torrent_file);
-        tr_info inf;
+        auto inf = tr_info{};
         auto parse_result = tr_torrentParse(ctor, &inf);
         EXPECT_EQ(TR_PARSE_OK, parse_result);
 
diff --git a/tests/libtransmission/metainfo-test.cc b/tests/libtransmission/metainfo-test.cc
index f1fccbf68..712f6a45a 100644
--- a/tests/libtransmission/metainfo-test.cc
+++ b/tests/libtransmission/metainfo-test.cc
@@ -29,7 +29,7 @@ TEST(Metainfo, magnetLink)
 
     auto* ctor = tr_ctorNew(nullptr);
     tr_ctorSetMetainfoFromMagnetLink(ctor, MagnetLink);
-    tr_info inf;
+    auto inf = tr_info{};
     auto const parse_result = tr_torrentParse(ctor, &inf);
     EXPECT_EQ(TR_PARSE_OK, parse_result);
     EXPECT_EQ(0, inf.fileCount); // because it's a magnet link