diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index be53e24a..2dfc4274 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -23,6 +23,16 @@ jobs:
           (find . -name "*.py" -and -not -name "conanfile.py"; grep -lR '^#!.*python') \
               | xargs -n1 -P8 mypy --strict
 
+  tokstyle:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Docker Build
+        uses: docker/build-push-action@v2
+        with:
+          file: other/docker/tokstyle/Dockerfile
+
   build-msan:
     runs-on: ubuntu-latest
     steps:
diff --git a/other/docker/typecheck/Dockerfile b/other/docker/tokstyle/Dockerfile
similarity index 78%
rename from other/docker/typecheck/Dockerfile
rename to other/docker/tokstyle/Dockerfile
index 72ee50a7..ba660e24 100644
--- a/other/docker/typecheck/Dockerfile
+++ b/other/docker/tokstyle/Dockerfile
@@ -6,13 +6,16 @@ RUN apt-get update && apt-get install --no-install-recommends -y \
  gcc \
  git \
  libmsgpack-dev \
+ libopus-dev \
  libsodium-dev \
+ libvpx-dev \
  && apt-get clean \
  && rm -rf /var/lib/apt/lists/*
 
 COPY --from=tokstyle /bin/check-c /bin/
 RUN ["git", "clone", "--depth=1", "https://github.com/TokTok/hs-tokstyle", "/src/workspace/hs-tokstyle"]
 
+COPY toxav/ /src/workspace/c-toxcore/toxcore/
 COPY toxcore/ /src/workspace/c-toxcore/toxcore/
 COPY toxencryptsave/ /src/workspace/c-toxcore/toxencryptsave/
-RUN /bin/check-c /src/workspace/c-toxcore/toxcore/*.c
+RUN /bin/check-c $(find /src/workspace/c-toxcore -name "*.c")
diff --git a/other/docker/tokstyle/run b/other/docker/tokstyle/run
new file mode 100755
index 00000000..30c2a738
--- /dev/null
+++ b/other/docker/tokstyle/run
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+docker build -f other/docker/tokstyle/Dockerfile .
diff --git a/other/docker/typecheck/run b/other/docker/typecheck/run
deleted file mode 100755
index 006eeb94..00000000
--- a/other/docker/typecheck/run
+++ /dev/null
@@ -1,3 +0,0 @@
-#!/bin/sh
-
-docker build -f other/docker/typecheck/Dockerfile .
diff --git a/toxav/audio.c b/toxav/audio.c
index 5369a1e1..536f6916 100644
--- a/toxav/audio.c
+++ b/toxav/audio.c
@@ -191,7 +191,7 @@ void ac_iterate(ACSession *ac)
 
         if (rc < 0) {
             LOGGER_WARNING(ac->log, "Decoding error: %s", opus_strerror(rc));
-        } else if (ac->acb) {
+        } else if (ac->acb != nullptr) {
             ac->lp_frame_duration = (rc * 1000) / ac->lp_sampling_rate;
 
             ac->acb(ac->av, ac->friend_number, temp_audio_buffer, rc, ac->lp_channel_count,
@@ -324,7 +324,7 @@ static int jbuf_write(const Logger *log, struct JitterBuffer *q, struct RTPMessa
         return 0;
     }
 
-    if (q->queue[num]) {
+    if (q->queue[num] != nullptr) {
         return -1;
     }
 
@@ -345,7 +345,7 @@ static struct RTPMessage *jbuf_read(struct JitterBuffer *q, int32_t *success)
 
     unsigned int num = q->bottom % q->size;
 
-    if (q->queue[num]) {
+    if (q->queue[num] != nullptr) {
         struct RTPMessage *ret = q->queue[num];
         q->queue[num] = nullptr;
         ++q->bottom;
diff --git a/toxav/groupav.c b/toxav/groupav.c
index 37a64553..582cd84d 100644
--- a/toxav/groupav.c
+++ b/toxav/groupav.c
@@ -110,7 +110,7 @@ static int queue(Group_JitterBuffer *q, const Mono_Time *mono_time, Group_Audio_
         return 0;
     }
 
-    if (q->queue[num]) {
+    if (q->queue[num] != nullptr) {
         return -1;
     }
 
@@ -134,7 +134,7 @@ static Group_Audio_Packet *dequeue(Group_JitterBuffer *q, int *success)
 
     unsigned int num = q->bottom % q->size;
 
-    if (q->queue[num]) {
+    if (q->queue[num] != nullptr) {
         Group_Audio_Packet *ret = q->queue[num];
         q->queue[num] = nullptr;
         ++q->bottom;
@@ -179,7 +179,7 @@ typedef struct Group_Peer_AV {
 
 static void kill_group_av(Group_AV *group_av)
 {
-    if (group_av->audio_encoder) {
+    if (group_av->audio_encoder != nullptr) {
         opus_encoder_destroy(group_av->audio_encoder);
     }
 
@@ -188,7 +188,7 @@ static void kill_group_av(Group_AV *group_av)
 
 static int recreate_encoder(Group_AV *group_av)
 {
-    if (group_av->audio_encoder) {
+    if (group_av->audio_encoder != nullptr) {
         opus_encoder_destroy(group_av->audio_encoder);
         group_av->audio_encoder = nullptr;
     }
@@ -272,7 +272,7 @@ static void group_av_peer_delete(void *object, uint32_t groupnumber, void *peer_
         return;
     }
 
-    if (peer_av->audio_decoder) {
+    if (peer_av->audio_decoder != nullptr) {
         opus_decoder_destroy(peer_av->audio_decoder);
     }
 
@@ -282,7 +282,7 @@ static void group_av_peer_delete(void *object, uint32_t groupnumber, void *peer_
 
 static void group_av_groupchat_delete(void *object, uint32_t groupnumber)
 {
-    if (object) {
+    if (object != nullptr) {
         kill_group_av((Group_AV *)object);
     }
 }
@@ -320,7 +320,7 @@ static int decode_audio_packet(Group_AV *group_av, Group_Peer_AV *peer_av, uint3
         }
 
         if (channels != peer_av->decoder_channels) {
-            if (peer_av->audio_decoder) {
+            if (peer_av->audio_decoder != nullptr) {
                 opus_decoder_destroy(peer_av->audio_decoder);
                 peer_av->audio_decoder = nullptr;
             }
@@ -379,9 +379,9 @@ static int decode_audio_packet(Group_AV *group_av, Group_Peer_AV *peer_av, uint3
         }
     }
 
-    if (out_audio) {
+    if (out_audio != nullptr) {
 
-        if (group_av->audio_data) {
+        if (group_av->audio_data != nullptr) {
             group_av->audio_data(group_av->tox, groupnumber, friendgroupnumber, out_audio, out_audio_samples,
                                  peer_av->decoder_channels, sample_rate, group_av->userdata);
         }
diff --git a/toxav/msi.c b/toxav/msi.c
index 396edcd5..62dc3e46 100644
--- a/toxav/msi.c
+++ b/toxav/msi.c
@@ -164,7 +164,7 @@ int msi_kill(MSISession *session, const Logger *log)
         return -1;
     }
 
-    if (session->calls) {
+    if (session->calls != nullptr) {
         MSIMessage msg;
         msg_init(&msg, REQU_POP);
 
@@ -625,17 +625,17 @@ static void kill_call(MSICall *call)
     MSICall *prev = call->prev;
     MSICall *next = call->next;
 
-    if (prev) {
+    if (prev != nullptr) {
         prev->next = next;
-    } else if (next) {
+    } else if (next != nullptr) {
         session->calls_head = next->friend_number;
     } else {
         goto CLEAR_CONTAINER;
     }
 
-    if (next) {
+    if (next != nullptr) {
         next->prev = prev;
-    } else if (prev) {
+    } else if (prev != nullptr) {
         session->calls_tail = prev->friend_number;
     } else {
         goto CLEAR_CONTAINER;
diff --git a/toxav/ring_buffer.c b/toxav/ring_buffer.c
index e8f79338..7336c197 100644
--- a/toxav/ring_buffer.c
+++ b/toxav/ring_buffer.c
@@ -85,7 +85,7 @@ RingBuffer *rb_new(int size)
 
 void rb_kill(RingBuffer *b)
 {
-    if (b) {
+    if (b != nullptr) {
         free(b->data);
         free(b);
     }
diff --git a/toxav/rtp.c b/toxav/rtp.c
index abd7d44d..7b39fd87 100644
--- a/toxav/rtp.c
+++ b/toxav/rtp.c
@@ -423,7 +423,7 @@ static int handle_video_packet(RTPSession *session, const struct RTPHeader *head
 
     struct RTPMessage *m_new = process_frame(log, session->work_buffer_list, slot_id);
 
-    if (m_new) {
+    if (m_new != nullptr) {
         LOGGER_DEBUG(log, "-- handle_video_packet -- CALLBACK-003a b0=%d b1=%d", (int)m_new->data[0], (int)m_new->data[1]);
         update_bwc_values(log, session, m_new);
         session->mcb(session->m->mono_time, session->cs, m_new);
@@ -498,7 +498,7 @@ static int handle_rtp_packet(Messenger *m, uint32_t friendnumber, const uint8_t
         bwc_add_recv(session->bwc, length);
 
         /* Invoke processing of active multiparted message */
-        if (session->mp) {
+        if (session->mp != nullptr) {
             session->mcb(session->m->mono_time, session->cs, session->mp);
             session->mp = nullptr;
         }
@@ -512,7 +512,7 @@ static int handle_rtp_packet(Messenger *m, uint32_t friendnumber, const uint8_t
 
     /* The message is sent in multiple parts */
 
-    if (session->mp) {
+    if (session->mp != nullptr) {
         /* There are 2 possible situations in this case:
          *      1) being that we got the part of already processing message.
          *      2) being that we got the part of a new/old message.
diff --git a/toxav/toxav.c b/toxav/toxav.c
index 74354a47..946b4e2c 100644
--- a/toxav/toxav.c
+++ b/toxav/toxav.c
@@ -160,7 +160,7 @@ ToxAV *toxav_new(Tox *tox, Toxav_Err_New *error)
     m = *(Messenger **)tox;
     //!TOKSTYLE+
 
-    if (m->msi_packet) {
+    if (m->msi_packet != nullptr) {
         rc = TOXAV_ERR_NEW_MULTIPLE;
         goto RETURN;
     }
@@ -203,7 +203,7 @@ ToxAV *toxav_new(Tox *tox, Toxav_Err_New *error)
 
 RETURN:
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -229,7 +229,7 @@ void toxav_kill(ToxAV *av)
     }
 
     /* Msi kill will hang up all calls so just clean these calls */
-    if (av->calls) {
+    if (av->calls != nullptr) {
         ToxAVCall *it = call_get(av, av->calls_head);
 
         while (it) {
@@ -400,7 +400,7 @@ bool toxav_call(ToxAV *av, uint32_t friend_number, uint32_t audio_bit_rate, uint
 RETURN:
     pthread_mutex_unlock(av->mutex);
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -460,7 +460,7 @@ bool toxav_answer(ToxAV *av, uint32_t friend_number, uint32_t audio_bit_rate, ui
 RETURN:
     pthread_mutex_unlock(av->mutex);
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -632,7 +632,7 @@ bool toxav_call_control(ToxAV *av, uint32_t friend_number, Toxav_Call_Control co
 
     pthread_mutex_unlock(av->mutex);
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -704,7 +704,7 @@ bool toxav_audio_set_bit_rate(ToxAV *av, uint32_t friend_number, uint32_t audio_
     pthread_mutex_unlock(av->mutex);
 RETURN:
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -776,7 +776,7 @@ bool toxav_video_set_bit_rate(ToxAV *av, uint32_t friend_number, uint32_t video_
     pthread_mutex_unlock(av->mutex);
 RETURN:
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -874,7 +874,7 @@ bool toxav_audio_send_frame(ToxAV *av, uint32_t friend_number, const int16_t *pc
 
 RETURN:
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -1022,7 +1022,7 @@ bool toxav_video_send_frame(ToxAV *av, uint32_t friend_number, uint16_t width, u
 
 RETURN:
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -1111,7 +1111,7 @@ static int callback_invite(void *toxav_inst, MSICall *call)
     call->av_call = av_call;
     av_call->msi_call = call;
 
-    if (toxav->ccb) {
+    if (toxav->ccb != nullptr) {
         toxav->ccb(toxav, call->friend_number, call->peer_capabilities & MSI_CAP_S_AUDIO,
                    call->peer_capabilities & MSI_CAP_S_VIDEO, toxav->ccb_user_data);
     } else {
@@ -1158,7 +1158,7 @@ static int callback_end(void *toxav_inst, MSICall *call)
 
     invoke_call_state_callback(toxav, call->friend_number, TOXAV_FRIEND_CALL_STATE_FINISHED);
 
-    if (call->av_call) {
+    if (call->av_call != nullptr) {
         call_kill_transmission(call->av_call);
         call_remove(call->av_call);
     }
@@ -1173,7 +1173,7 @@ static int callback_error(void *toxav_inst, MSICall *call)
 
     invoke_call_state_callback(toxav, call->friend_number, TOXAV_FRIEND_CALL_STATE_ERROR);
 
-    if (call->av_call) {
+    if (call->av_call != nullptr) {
         call_kill_transmission(call->av_call);
         call_remove(call->av_call);
     }
@@ -1219,11 +1219,11 @@ static bool video_bit_rate_invalid(uint32_t bit_rate)
      * we may want to prevent from passing overflowed bitrates to libvpx
      * more in detail, it's the case where bit_rate is larger than uint, but smaller than uint32_t
      */
-    return bit_rate > UINT_MAX;
+    return bit_rate > UINT32_MAX;
 }
 static bool invoke_call_state_callback(ToxAV *av, uint32_t friend_number, uint32_t state)
 {
-    if (av->scb) {
+    if (av->scb != nullptr) {
         av->scb(av, friend_number, state, av->scb_user_data);
     } else {
         return false;
@@ -1315,7 +1315,7 @@ static ToxAVCall *call_new(ToxAV *av, uint32_t friend_number, Toxav_Err_Call *er
 
 RETURN:
 
-    if (error) {
+    if (error != nullptr) {
         *error = rc;
     }
 
@@ -1347,24 +1347,24 @@ static ToxAVCall *call_remove(ToxAVCall *call)
     /* Set av call in msi to NULL in order to know if call if ToxAVCall is
      * removed from the msi call.
      */
-    if (call->msi_call) {
+    if (call->msi_call != nullptr) {
         call->msi_call->av_call = nullptr;
     }
 
     pthread_mutex_destroy(call->toxav_call_mutex);
     free(call);
 
-    if (prev) {
+    if (prev != nullptr) {
         prev->next = next;
-    } else if (next) {
+    } else if (next != nullptr) {
         av->calls_head = next->friend_number;
     } else {
         goto CLEAR;
     }
 
-    if (next) {
+    if (next != nullptr) {
         next->prev = prev;
-    } else if (prev) {
+    } else if (prev != nullptr) {
         av->calls_tail = prev->friend_number;
     } else {
         goto CLEAR;
diff --git a/toxav/video.c b/toxav/video.c
index e62fc3bf..db154026 100644
--- a/toxav/video.c
+++ b/toxav/video.c
@@ -330,7 +330,7 @@ void vc_iterate(VCSession *vc)
     for (vpx_image_t *dest = vpx_codec_get_frame(vc->decoder, &iter);
             dest != nullptr;
             dest = vpx_codec_get_frame(vc->decoder, &iter)) {
-        if (vc->vcb) {
+        if (vc->vcb != nullptr) {
             vc->vcb(vc->av, vc->friend_number, dest->d_w, dest->d_h,
                     (const uint8_t *)dest->planes[0], (const uint8_t *)dest->planes[1], (const uint8_t *)dest->planes[2],
                     dest->stride[0], dest->stride[1], dest->stride[2], vc->vcb_user_data);
@@ -347,7 +347,7 @@ int vc_queue_message(Mono_Time *mono_time, void *vcp, struct RTPMessage *msg)
      * this function gets called from handle_rtp_packet() and handle_rtp_packet_v3()
      */
     if (!vcp || !msg) {
-        if (msg) {
+        if (msg != nullptr) {
             free(msg);
         }