diff --git a/daemon/daemon-posix.c b/daemon/daemon-posix.c
index 834b6ce99..fdae6dd95 100644
--- a/daemon/daemon-posix.c
+++ b/daemon/daemon-posix.c
@@ -11,7 +11,7 @@
 #include <errno.h>
 #include <pthread.h>
 #include <signal.h>
-#include <stdlib.h> /* daemon (), exit () */
+#include <stdlib.h> /* abort (), daemon (), exit () */
 #include <fcntl.h> /* open () */
 #include <unistd.h> /* fork (), setsid (), chdir (), dup2 (), close (), pipe () */
 
@@ -70,7 +70,8 @@ send_signal_to_pipe (int sig)
 {
   const int old_errno = errno;
 
-  write (signal_pipe[1], &sig, sizeof (sig));
+  if (write (signal_pipe[1], &sig, sizeof (sig)) == -1)
+    abort ();
 
   errno = old_errno;
 }
diff --git a/libtransmission/torrent.c b/libtransmission/torrent.c
index b2837a417..6770b7a03 100644
--- a/libtransmission/torrent.c
+++ b/libtransmission/torrent.c
@@ -2178,7 +2178,8 @@ torrentCallScript (const tr_torrent * tor, const char * script)
           for (i = 0; env[i] != NULL; ++i)
             putenv (env[i]);
 
-          (void) chdir ("/");
+          if (chdir ("/") == -1)
+            /* ignore (nice to have but not that critical) */;
 
           if (execvp (script, cmd) == -1)
             tr_logAddTorErr (tor, "error executing script \"%s\": %s", script, tr_strerror (errno));
diff --git a/libtransmission/tr-lpd.c b/libtransmission/tr-lpd.c
index 09733f42c..ba6a38741 100644
--- a/libtransmission/tr-lpd.c
+++ b/libtransmission/tr-lpd.c
@@ -404,7 +404,8 @@ tr_lpdEnabled (const tr_session* ss)
 * @remark Declared inline for the compiler not to allege us of feeding unused
 * functions. In any other respect, lpd_consistencyCheck is an orphaned function.
 */
-static inline void lpd_consistencyCheck (void)
+UNUSED static inline void
+lpd_consistencyCheck (void)
 {
     /* if the following check fails, the definition of a hash string has changed
      * without our knowledge; revise string handling in functions tr_lpdSendAnnounce
diff --git a/libtransmission/utils.c b/libtransmission/utils.c
index ea3b75a5a..b08f4fb40 100644
--- a/libtransmission/utils.c
+++ b/libtransmission/utils.c
@@ -812,7 +812,7 @@ tr_urlParse (const char  * url,
 
   const char * host_end = memchr (authority, ':', authority_len);
 
-  const size_t host_len = host_end != NULL ? host_end - authority : authority_len;
+  const size_t host_len = host_end != NULL ? (size_t) (host_end - authority) : authority_len;
   if (host_len == 0)
     return false;
 
diff --git a/libtransmission/utils.h b/libtransmission/utils.h
index 1fe5c4c79..13b34dc15 100644
--- a/libtransmission/utils.h
+++ b/libtransmission/utils.h
@@ -360,10 +360,10 @@ void tr_hex_to_binary (const char * input, void * output, size_t byte_length) TR
 bool tr_addressIsIP (const char * address);
 
 /** @brief return true if the url is a http or https or UDP url that Transmission understands */
-bool tr_urlIsValidTracker (const char * url) TR_GNUC_NONNULL (1);
+bool tr_urlIsValidTracker (const char * url);
 
 /** @brief return true if the url is a [ http, https, ftp, sftp ] url that Transmission understands */
-bool tr_urlIsValid (const char * url, size_t url_len) TR_GNUC_NONNULL (1);
+bool tr_urlIsValid (const char * url, size_t url_len);
 
 /** @brief parse a URL into its component parts
     @return True on success or false if an error occurred */