diff --git a/src/alchemy.c b/src/alchemy.c
index 1673d5196..43de02462 100644
--- a/src/alchemy.c
+++ b/src/alchemy.c
@@ -67,7 +67,7 @@ void new_potiontype(item_type * itype, int level)
     potion_type *ptype;
 
     ptype = (potion_type *)calloc(1, sizeof(potion_type));
-    assert(ptype);
+    assert(ptype != NULL);
     itype->flags |= ITF_POTION;
     ptype->itype = itype;
     ptype->level = level;
@@ -120,7 +120,7 @@ void herbsearch(unit * u, int max_take)
 
     if (herbsfound) {
         produceexp(u, SK_HERBALISM, u->number);
-        i_change(&u->items, whichherb, herbsfound);
+        (void)i_change(&u->items, whichherb, herbsfound);
         ADDMSG(&u->faction->msgs, msg_message("herbfound",
             "unit region amount herb", u, r, herbsfound, whichherb->rtype));
     }
diff --git a/src/kernel/building.c b/src/kernel/building.c
index 09a515fc3..fc90ebe94 100644
--- a/src/kernel/building.c
+++ b/src/kernel/building.c
@@ -27,6 +27,7 @@ OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 #include <spells/regioncurse.h>
 
 /* kernel includes */
+
 #include "curse.h"
 #include "item.h"
 #include "unit.h"
@@ -95,7 +96,7 @@ static int bt_changes = 1;
 
 bool bt_changed(int *cache)
 {
-    assert(cache);
+    assert(cache != NULL);
     if (*cache != bt_changes) {
         *cache = bt_changes;
         return true;
@@ -108,7 +109,7 @@ static void bt_register(building_type * btype)
     size_t len;
     char data[64];
 
-    selist_push(&buildingtypes, (void *)btype);
+    (void)selist_push(&buildingtypes, (void *)btype);
     len = cb_new_kv(btype->_name, strlen(btype->_name), &btype, sizeof(btype), data);
     assert(len <= sizeof(data));
     cb_insert(&cb_bldgtypes, data, len);
@@ -129,20 +130,25 @@ static void free_buildingtype(void *ptr) {
     free(btype);
 }
 
+static building_type *bt_create(const char *name) {
+    building_type *btype = (building_type *)calloc(1, sizeof(building_type));
+    if (!btype) abort();
+    btype->_name = str_strdup(name);
+    btype->flags = BTF_DEFAULT;
+    btype->auraregen = 1.0;
+    btype->maxsize = -1;
+    btype->capacity = 1;
+    btype->maxcapacity = -1;
+    return btype;
+}
+
 building_type *bt_get_or_create(const char *name)
 {
     assert(name && name[0]);
     if (name != NULL) {
         building_type *btype = bt_find_i(name);
         if (btype == NULL) {
-            btype = (building_type *)calloc(1, sizeof(building_type));
-            if (!btype) abort();
-            btype->_name = str_strdup(name);
-            btype->flags = BTF_DEFAULT;
-            btype->auraregen = 1.0;
-            btype->maxsize = -1;
-            btype->capacity = 1;
-            btype->maxcapacity = -1;
+            btype = bt_create(name);
             bt_register(btype);
         }
         return btype;
@@ -174,7 +180,7 @@ attrib_type at_building_generic_type = {
 
 /* TECH DEBT: simplest thing that works for E3 dwarf/halfling faction rules */
 static int adjust_size(const building *b, int bsize) {
-    assert(b);
+    assert(b != NULL);
     if (config_get_int("rules.dwarf_castles", 0)
         && strcmp(b->type->_name, "castle") == 0) {
         unit *u = building_owner(b);
@@ -190,7 +196,7 @@ static int adjust_size(const building *b, int bsize) {
  */
 const char *buildingtype(const building_type * btype, const building * b, int bsize)
 {
-    assert(btype);
+    assert(btype != NULL);
 
     if (b && b->attribs) {
         if (is_building_type(btype, "generic")) {
@@ -411,7 +417,7 @@ building *new_building(const struct building_type * btype, region * r,
             bname = parameters[P_GEBAEUDE];
         }
     }
-    assert(bname);
+    assert(bname != NULL);
     snprintf(buffer, sizeof(buffer), "%s %s", bname, itoa36(b->no));
     b->name = str_strdup(bname);
     return b;
@@ -429,7 +435,7 @@ void remove_building(building ** blist, building * b)
     static const struct building_type *bt_caravan, *bt_dam, *bt_tunnel;
     static int btypes;
 
-    assert(bfindhash(b->no));
+    assert(bfindhash(b->no) != NULL);
 
     if (bt_changed(&btypes)) {
         bt_caravan = bt_find("caravan");
@@ -690,7 +696,7 @@ bool in_safe_building(unit *u1, unit *u2) {
 }
 
 bool is_building_type(const struct building_type *btype, const char *name) {
-    assert(btype);
+    assert(btype != NULL);
     return name && strcmp(btype->_name, name)==0;
 }
 
@@ -826,7 +832,7 @@ int cmp_wage(const struct building *b, const building * a)
 }
 
 int building_taxes(const building *b) {
-    assert(b);
+    assert(b != NULL);
     return b->type->taxes;
 }
 
diff --git a/src/kernel/gamedata.h b/src/kernel/gamedata.h
index 77469f9da..e14c0a551 100644
--- a/src/kernel/gamedata.h
+++ b/src/kernel/gamedata.h
@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 
 #ifndef _GAMEDATA_H
 #define _GAMEDATA_H
diff --git a/src/kernel/messages.h b/src/kernel/messages.h
index 7fa6996e2..ea0afc870 100644
--- a/src/kernel/messages.h
+++ b/src/kernel/messages.h
@@ -55,7 +55,7 @@ extern "C" {
     struct mlist ** merge_messages(message_list *ml, message_list *append);
     void split_messages(message_list *ml, struct mlist **split);
 
-#define ADDMSG(msgs, mcreate) { message * mx = mcreate; if (mx) { add_message(msgs, mx); msg_release(mx); } }
+#define ADDMSG(msgs, mcreate) { message * mx = mcreate; if (mx) { (void)add_message(msgs, mx); msg_release(mx); } }
 
     void syntax_error(const struct unit *u, struct order *ord);
     void cmistake(const struct unit *u, struct order *ord, int mno, int mtype);
diff --git a/src/util/strings.c b/src/util/strings.c
index 7f6cad26c..1158d40f4 100644
--- a/src/util/strings.c
+++ b/src/util/strings.c
@@ -64,8 +64,8 @@ size_t str_strlcpy(char *dst, const char *src, size_t len)
     register const char *s = src;
     register size_t n = len;
 
-    assert(src);
-    assert(dst);
+    assert(src != NULL);
+    assert(dst != NULL);
     /* Copy as many bytes as will fit */
     if (n != 0 && --n != 0) {
         do {
@@ -82,7 +82,7 @@ size_t str_strlcpy(char *dst, const char *src, size_t len)
         return (s - src) + strlen(s); /* count does not include NUL */
     }
 
-    return (s - src - 1);         /* count does not include NUL */
+    return (size_t)(s - src - 1);         /* count does not include NUL */
 #endif
 }
 
@@ -99,7 +99,7 @@ size_t str_strlcat(char *dst, const char *src, size_t len)
     /* Find the end of dst and adjust bytes left but don't go past end */
     while (*d != '\0' && n-- != 0)
         d++;
-    dlen = d - dst;
+    dlen = (size_t)(d - dst);
     n = len - dlen;
 
     if (n == 0)
@@ -143,7 +143,7 @@ void str_replace(char *buffer, size_t size, const char *tmpl, const char *var,
         char *p = strstr(tmpl, var);
         size_t len;
         if (p) {
-            len = p - tmpl;
+            len = (size_t)(p - tmpl);
         }
         else {
             len = strlen(tmpl);
@@ -170,7 +170,7 @@ void str_replace(char *buffer, size_t size, const char *tmpl, const char *var,
 int str_hash(const char *s)
 {
     int key = 0;
-    assert(s);
+    assert(s != NULL);
     while (*s) {
         key = key * 37 + *s++;
     }
@@ -200,17 +200,19 @@ unsigned int wang_hash(unsigned int a)
 }
 
 char *str_strdup(const char *s) {
-    if (s == NULL) return NULL;
+    if (s != NULL) {
 #ifdef HAVE_STRDUP
-    return strdup(s);
+        return strdup(s);
 #elif defined(_MSC_VER)
-    return _strdup(s);
+        return _strdup(s);
 #else
-    size_t len = strlen(s);
-    char *dup = malloc(len+1);
-    memcpy(dup, s, len+1);
-    return dup;
+        size_t len = strlen(s);
+        char *dup = malloc(len+1);
+        memcpy(dup, s, len+1);
+        return dup;
 #endif
+    }
+    return NULL;
 }
 
 void sbs_printf(struct sbstring *sbs, const char *format, ...)
@@ -218,16 +220,18 @@ void sbs_printf(struct sbstring *sbs, const char *format, ...)
     size_t size = sbs->size - (sbs->end - sbs->begin);
 
     if (size > 0) {
+        int bytes;
         va_list argp;
         va_start(argp, format);
-        int bytes = vsnprintf(sbs->end, size, format, argp);
+        bytes = vsnprintf(sbs->end, size, format, argp);
         if (bytes > 0) {
-            if ((size_t)bytes >= size) {
-                bytes = size - 1;
+            size_t len = (size_t)bytes;
+            if (len >= size) {
+                len = size - 1;
                 /* terminate truncated output */
-                sbs->end[bytes] = '\0';
+                sbs->end[len] = '\0';
             }
-            sbs->end += bytes;
+            sbs->end += len;
         }
         va_end(argp);
     }
@@ -235,7 +239,7 @@ void sbs_printf(struct sbstring *sbs, const char *format, ...)
 
 void sbs_init(struct sbstring *sbs, char *buffer, size_t size)
 {
-    assert(sbs);
+    assert(sbs != NULL);
     assert(size > 0);
     sbs->begin = buffer;
     sbs->size = size;
@@ -246,7 +250,7 @@ void sbs_init(struct sbstring *sbs, char *buffer, size_t size)
 void sbs_adopt(struct sbstring *sbs, char *buffer, size_t size)
 {
     size_t len = strlen(buffer);
-    assert(sbs);
+    assert(sbs != NULL);
     assert(size > len);
     sbs->begin = buffer;
     sbs->size = size;
@@ -256,7 +260,7 @@ void sbs_adopt(struct sbstring *sbs, char *buffer, size_t size)
 void sbs_strncat(struct sbstring *sbs, const char *str, size_t size)
 {
     size_t len;
-    assert(sbs);
+    assert(sbs != NULL);
     len = sbs->size - (sbs->end - sbs->begin) - 1;
     if (len < size) {
         size = len;
@@ -269,21 +273,21 @@ void sbs_strncat(struct sbstring *sbs, const char *str, size_t size)
 void sbs_strcat(struct sbstring *sbs, const char *str)
 {
     size_t len;
-    assert(sbs);
+    assert(sbs != NULL);
     len = sbs->size - (sbs->end - sbs->begin);
-    str_strlcpy(sbs->end, str, len);
+    (void)str_strlcpy(sbs->end, str, len);
     sbs->end += strlen(sbs->end);
     assert(sbs->begin + sbs->size >= sbs->end);
 }
 
 void sbs_substr(sbstring *sbs, ptrdiff_t pos, size_t len)
 {
-    if (pos > sbs->end - sbs->begin) {
+    if (sbs->begin + pos > sbs->end) {
         /* starting past end of string, do nothing */
         sbs->end = sbs->begin;
     }
     if (pos >= 0) {
-        size_t sz = sbs->end - (sbs->begin + pos);
+        size_t sz = sbs->end - sbs->begin - pos;
         if (len > sz) len = sz;
         if (len - pos > 0) {
             memmove(sbs->begin, sbs->begin + pos, len);
@@ -299,15 +303,15 @@ void sbs_substr(sbstring *sbs, ptrdiff_t pos, size_t len)
 size_t sbs_length(const struct sbstring *sbs)
 {
     assert(sbs->begin + sbs->size >= sbs->end);
-    return sbs->end - sbs->begin;
+    return (size_t)(sbs->end - sbs->begin);
 }
 
 char *str_unescape(char *str) {
     char *read = str, *write = str;
     while (*read) {
         char * pos = strchr(read, '\\');
-        if (pos) {
-            size_t len = pos - read;
+        if (pos > read) {
+            size_t len = (size_t)(pos - read);
             memmove(write, read, len);
             write += len;
             read += (len + 1);
@@ -341,15 +345,15 @@ const char *str_escape_ex(const char *str, char *buffer, size_t size, const char
 {
     size_t slen = strlen(str);
     const char *read = str;
-    char *write = buffer;
+    unsigned char *write = (unsigned char *)buffer;
     if (size < 1) {
         return NULL;
     }
     while (slen > 0 && size > 1 && *read) {
         const char *pos = strpbrk(read, chars);
         size_t len = size;
-        if (pos) {
-            len = pos - read;
+        if (pos > read) {
+            len = (size_t)(pos - read);
         }
         if (len < size) {
             unsigned char ch = *(const unsigned char *)pos;
@@ -399,7 +403,7 @@ const char *str_escape_ex(const char *str, char *buffer, size_t size, const char
                 break;
             default:
                 if (size > 5) {
-                    int n = sprintf(write, "\\%03o", ch);
+                    int n = snprintf((char *)write, size, "\\%03o", ch);
                     if (n > 0) {
                         assert(n == 5);
                         write += n;