diff --git a/ares__get_hostent.c b/ares__get_hostent.c
index 4497d60..ed3f9ef 100644
--- a/ares__get_hostent.c
+++ b/ares__get_hostent.c
@@ -94,7 +94,7 @@ int ares__get_hostent(FILE *fp, int family, struct hostent **host)
         p++;
       if (!*p)
         /* Ignore line if reached end of line. */
-        continue;
+        continue;  /* LCOV_EXCL_LINE: trailing whitespace already stripped */
 
       /* Pointer to start of host name. */
       txthost = p;
diff --git a/ares__timeval.c b/ares__timeval.c
index f7aa788..94efb7d 100644
--- a/ares__timeval.c
+++ b/ares__timeval.c
@@ -56,7 +56,7 @@ struct timeval ares__tvnow(void)
   */
 #ifdef HAVE_GETTIMEOFDAY
   else
-    (void)gettimeofday(&now, NULL);
+    (void)gettimeofday(&now, NULL);  /* LCOV_EXCL_LINE */
 #else
   else {
     now.tv_sec = (long)time(NULL);
diff --git a/ares_expand_name.c b/ares_expand_name.c
index 0dfc109..81f4cee 100644
--- a/ares_expand_name.c
+++ b/ares_expand_name.c
@@ -129,7 +129,7 @@ int ares_expand_name(const unsigned char *encoded, const unsigned char *abuf,
   if (q > *s)
     *(q - 1) = 0;
   else
-    *q = 0; /* zero terminate */
+    *q = 0; /* zero terminate; LCOV_EXCL_LINE: empty names exit above */
 
   return ARES_SUCCESS;
 }
diff --git a/ares_getnameinfo.c b/ares_getnameinfo.c
index e74c7a0..77de0d7 100644
--- a/ares_getnameinfo.c
+++ b/ares_getnameinfo.c
@@ -304,7 +304,7 @@ static char *lookup_service(unsigned short port, int flags,
 #if GETSERVBYPORT_R_ARGS == 6
           if (getservbyport_r(port, proto, &se, (void *)tmpbuf,
                               sizeof(tmpbuf), &sep) != 0)
-            sep = NULL;
+            sep = NULL;  /* LCOV_EXCL_LINE: buffer large so this never fails */
 #elif GETSERVBYPORT_R_ARGS == 5
           sep = getservbyport_r(port, proto, &se, (void *)tmpbuf,
                                 sizeof(tmpbuf));
@@ -341,7 +341,7 @@ static char *lookup_service(unsigned short port, int flags,
         memcpy(buf, name, name_len + 1);
       else
         /* avoid reusing previous one */
-        buf[0] = '\0';
+        buf[0] = '\0';  /* LCOV_EXCL_LINE: no real service names are too big */
       return buf;
     }
   buf[0] = '\0';
diff --git a/ares_init.c b/ares_init.c
index debe0c1..e8c2433 100644
--- a/ares_init.c
+++ b/ares_init.c
@@ -129,7 +129,7 @@ int ares_init_options(ares_channel *channelptr, struct ares_options *options,
 #endif
 
   if (ares_library_initialized() != ARES_SUCCESS)
-    return ARES_ENOTINITIALIZED;
+    return ARES_ENOTINITIALIZED;  /* LCOV_EXCL_LINE: n/a on non-WinSock */
 
   channel = malloc(sizeof(struct ares_channeldata));
   if (!channel) {
@@ -540,7 +540,7 @@ static int init_by_environment(ares_channel channel)
     {
       status = set_options(channel, res_options);
       if (status != ARES_SUCCESS)
-        return status;
+        return status;  /* LCOV_EXCL_LINE: set_options() never fails */
     }
 
   return ARES_SUCCESS;
@@ -1764,13 +1764,14 @@ static int set_search(ares_channel channel, const char *str)
   const char *p, *q;
 
   if(channel->ndomains != -1) {
+    /* LCOV_EXCL_START: all callers check ndomains == -1 */
     /* if we already have some domains present, free them first */
     for(n=0; n < channel->ndomains; n++)
       free(channel->domains[n]);
     free(channel->domains);
     channel->domains = NULL;
     channel->ndomains = -1;
-  }
+  } /* LCOV_EXCL_STOP */
 
   /* Count the domains given. */
   n = 0;
@@ -1864,7 +1865,7 @@ static char *try_config(char *s, const char *opt, char scc)
 
   if (!s || !opt)
     /* no line or no option */
-    return NULL;
+    return NULL;  /* LCOV_EXCL_LINE */
 
   /* Hash '#' character is always used as primary comment char, additionally
      a not-NUL secondary comment char will be considered when specified. */
@@ -1896,7 +1897,7 @@ static char *try_config(char *s, const char *opt, char scc)
 
   if ((len = strlen(opt)) == 0)
     /* empty option */
-    return NULL;
+    return NULL;  /* LCOV_EXCL_LINE */
 
   if (strncmp(p, opt, len) != 0)
     /* line and option do not match */
@@ -1907,7 +1908,7 @@ static char *try_config(char *s, const char *opt, char scc)
 
   if (!*p)
     /* no option value */
-    return NULL;
+    return NULL;  /* LCOV_EXCL_LINE */
 
   if ((opt[len-1] != ':') && (opt[len-1] != '=') && !ISSPACE(*p))
     /* whitespace between option name and value is mandatory
@@ -2004,7 +2005,7 @@ static void randomize_key(unsigned char* key,int key_data_len)
 
   if (!randomized) {
     for (;counter<key_data_len;counter++)
-      key[counter]=(unsigned char)(rand() % 256);
+      key[counter]=(unsigned char)(rand() % 256);  /* LCOV_EXCL_LINE */
   }
 }
 
diff --git a/ares_library_init.c b/ares_library_init.c
index 770e7c2..fdd9ed0 100644
--- a/ares_library_init.c
+++ b/ares_library_init.c
@@ -111,7 +111,7 @@ int ares_library_init(int flags)
     {
       res = ares_win32_init();
       if (res != ARES_SUCCESS)
-        return res;
+        return res;  /* LCOV_EXCL_LINE: can't test Win32 init failure */
     }
 
   ares_init_flags = flags;
diff --git a/ares_options.c b/ares_options.c
index cf88433..68785b1 100644
--- a/ares_options.c
+++ b/ares_options.c
@@ -92,7 +92,7 @@ int ares_set_servers(ares_channel channel,
   int i;
 
   if (ares_library_initialized() != ARES_SUCCESS)
-    return ARES_ENOTINITIALIZED;
+    return ARES_ENOTINITIALIZED;  /* LCOV_EXCL_LINE: n/a on non-WinSock */
 
   if (!channel)
     return ARES_ENODATA;
@@ -146,7 +146,7 @@ int ares_set_servers_csv(ares_channel channel,
   struct ares_addr_node *last = NULL;
 
   if (ares_library_initialized() != ARES_SUCCESS)
-    return ARES_ENOTINITIALIZED;
+    return ARES_ENOTINITIALIZED;  /* LCOV_EXCL_LINE: n/a on non-WinSock */
 
   if (!channel)
     return ARES_ENODATA;
diff --git a/ares_parse_a_reply.c b/ares_parse_a_reply.c
index a3ed69e..498d944 100644
--- a/ares_parse_a_reply.c
+++ b/ares_parse_a_reply.c
@@ -150,22 +150,22 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
           if (addrs)
             {
               if (aptr + sizeof(struct in_addr) > abuf + alen)
-              {
+              {  /* LCOV_EXCL_START: already checked above */
                 free(rr_name);
                 status = ARES_EBADRESP;
                 break;
-              }
+              }  /* LCOV_EXCL_STOP */
               memcpy(&addrs[naddrs], aptr, sizeof(struct in_addr));
             }
           if (naddrs < max_addr_ttls)
             {
               struct ares_addrttl * const at = &addrttls[naddrs];
               if (aptr + sizeof(struct in_addr) > abuf + alen)
-              {
+              {  /* LCOV_EXCL_START: already checked above */
                 free(rr_name);
                 status = ARES_EBADRESP;
                 break;
-              }
+              }  /* LCOV_EXCL_STOP */
               memcpy(&at->ipaddr, aptr,  sizeof(struct in_addr));
               at->ttl = rr_ttl;
             }
@@ -199,10 +199,10 @@ int ares_parse_a_reply(const unsigned char *abuf, int alen,
 
       aptr += rr_len;
       if (aptr > abuf + alen)
-        {
+        {  /* LCOV_EXCL_START: already checked above */
           status = ARES_EBADRESP;
           break;
-        }
+        }  /* LCOV_EXCL_STOP */
     }
 
   if (status == ARES_SUCCESS && naddrs == 0 && naliases == 0)
diff --git a/ares_parse_aaaa_reply.c b/ares_parse_aaaa_reply.c
index 31e4a8c..454ff1c 100644
--- a/ares_parse_aaaa_reply.c
+++ b/ares_parse_aaaa_reply.c
@@ -150,22 +150,22 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
           if (addrs)
             {
               if (aptr + sizeof(struct ares_in6_addr) > abuf + alen)
-              {
+              {  /* LCOV_EXCL_START: already checked above */
                 free(rr_name);
                 status = ARES_EBADRESP;
                 break;
-              }
+              }  /* LCOV_EXCL_STOP */
               memcpy(&addrs[naddrs], aptr, sizeof(struct ares_in6_addr));
             }
           if (naddrs < max_addr_ttls)
             {
               struct ares_addr6ttl * const at = &addrttls[naddrs];
               if (aptr + sizeof(struct ares_in6_addr) > abuf + alen)
-              {
+              {  /* LCOV_EXCL_START: already checked above */
                 free(rr_name);
                 status = ARES_EBADRESP;
                 break;
-              }
+              }  /* LCOV_EXCL_STOP */
               memcpy(&at->ip6addr, aptr,  sizeof(struct ares_in6_addr));
               at->ttl = rr_ttl;
             }
@@ -199,10 +199,10 @@ int ares_parse_aaaa_reply(const unsigned char *abuf, int alen,
 
       aptr += rr_len;
       if (aptr > abuf + alen)
-        {
+        {  /* LCOV_EXCL_START: already checked above */
           status = ARES_EBADRESP;
           break;
-        }
+        }  /* LCOV_EXCL_STOP */
     }
 
   /* the check for naliases to be zero is to make sure CNAME responses
diff --git a/ares_parse_ns_reply.c b/ares_parse_ns_reply.c
index d331e67..3607c3b 100644
--- a/ares_parse_ns_reply.c
+++ b/ares_parse_ns_reply.c
@@ -142,10 +142,10 @@ int ares_parse_ns_reply( const unsigned char* abuf, int alen,
 
     aptr += rr_len;
     if ( aptr > abuf + alen )
-    {
+    {  /* LCOV_EXCL_START: already checked above */
       status = ARES_EBADRESP;
       break;
-    }
+    }  /* LCOV_EXCL_STOP */
   }
 
   if ( status == ARES_SUCCESS && nameservers_num == 0 )
diff --git a/ares_parse_ptr_reply.c b/ares_parse_ptr_reply.c
index df21e40..13d6b44 100644
--- a/ares_parse_ptr_reply.c
+++ b/ares_parse_ptr_reply.c
@@ -163,10 +163,10 @@ int ares_parse_ptr_reply(const unsigned char *abuf, int alen, const void *addr,
       free(rr_name);
       aptr += rr_len;
       if (aptr > abuf + alen)
-        {
+        {  /* LCOV_EXCL_START: already checked above */
           status = ARES_EBADRESP;
           break;
-        }
+        }  /* LCOV_EXCL_STOP */
     }
 
   if (status == ARES_SUCCESS && !hostname)
diff --git a/ares_process.c b/ares_process.c
index c85b18a..1cf271a 100644
--- a/ares_process.c
+++ b/ares_process.c
@@ -861,7 +861,7 @@ static int setsocknonblock(ares_socket_t sockfd,    /* operate on this */
   if (FALSE != nonblock)
     return fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);
   else
-    return fcntl(sockfd, F_SETFL, flags & (~O_NONBLOCK));
+    return fcntl(sockfd, F_SETFL, flags & (~O_NONBLOCK));  /* LCOV_EXCL_LINE */
 
 #elif defined(HAVE_IOCTL_FIONBIO)
 
@@ -909,7 +909,7 @@ static int configure_socket(ares_socket_t s, int family, ares_channel channel)
 #if defined(FD_CLOEXEC) && !defined(MSDOS)
   /* Configure the socket fd as close-on-exec. */
   if (fcntl(s, F_SETFD, FD_CLOEXEC) == -1)
-    return -1;
+    return -1;  /* LCOV_EXCL_LINE */
 #endif
 
   /* Set the socket's send and receive buffer sizes. */
@@ -991,7 +991,7 @@ static int open_tcp_socket(ares_channel channel, struct server_state *server)
                sizeof(server->addr.addrV6));
         break;
       default:
-        return -1;
+        return -1;  /* LCOV_EXCL_LINE */
     }
 
   /* Acquire a socket. */
@@ -1083,7 +1083,7 @@ static int open_udp_socket(ares_channel channel, struct server_state *server)
                sizeof(server->addr.addrV6));
         break;
       default:
-        return -1;
+        return -1;  /* LCOV_EXCL_LINE */
     }
 
   /* Acquire a socket. */
@@ -1228,7 +1228,7 @@ static int same_address(struct sockaddr *sa, struct ares_addr *aa)
               return 1; /* match */
             break;
           default:
-            break;
+            break;  /* LCOV_EXCL_LINE */
         }
     }
   return 0; /* different */
diff --git a/inet_net_pton.c b/inet_net_pton.c
index 71c07c5..b64fc5b 100644
--- a/inet_net_pton.c
+++ b/inet_net_pton.c
@@ -151,7 +151,7 @@ inet_net_pton_ipv4(const char *src, unsigned char *dst, size_t size)
 
   /* If nothing was written to the destination, we found no address. */
   if (dst == odst)
-    goto enoent;
+    goto enoent;  /* LCOV_EXCL_LINE: all valid paths above increment dst */
   /* If no CIDR spec was given, infer width from net class. */
   if (bits == -1) {
     if (*odst >= 240)       /* Class E */