diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 11376fd..7c29618 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -17,8 +17,8 @@ else()
 endif()
 
 if(FLEX_FOUND)
-    FLEX_TARGET(sfst default-scanner.ll ${CMAKE_CURRENT_BINARY_DIR}/default-scanner.cpp)
-    FLEX_TARGET(sfst utf8-scanner.ll ${CMAKE_CURRENT_BINARY_DIR}/utf8-scanner.cpp)
+    FLEX_TARGET(sfst default-scanner.ll ${CMAKE_CURRENT_BINARY_DIR}/default-scanner.cpp COMPILE_FLAGS --nounput)
+    FLEX_TARGET(sfst utf8-scanner.ll ${CMAKE_CURRENT_BINARY_DIR}/utf8-scanner.cpp COMPILE_FLAGS --nounput)
 else()
     message(STATUS "Flex not found, so executables won't be generated.")
 endif()
diff --git a/src/compact.cpp b/src/compact.cpp
index 94d9543..279835e 100644
--- a/src/compact.cpp
+++ b/src/compact.cpp
@@ -289,7 +289,7 @@ void CompactTransducer::read_probs(FILE *file)
 
 {
   size_t n, m;
-  fread(&n, sizeof(n), 1, file);
+  (void)!fread(&n, sizeof(n), 1, file);
   if (fread(&m, sizeof(n), 1, file) != 1 || n != node_count() ||
       m != arc_count()) {
     fprintf(stderr, "Error: incompatible probability file!\n");
@@ -297,7 +297,7 @@ void CompactTransducer::read_probs(FILE *file)
   }
   final_logprob = new float[n];
   arc_logprob = new float[m];
-  fread(final_logprob, sizeof(float), n, file);
+  (void)!fread(final_logprob, sizeof(float), n, file);
   if (fread(arc_logprob, sizeof(float), n, file) != n) {
     fprintf(stderr, "Error: in probability file!\n");
     exit(1);
diff --git a/src/fst.cpp b/src/fst.cpp
index c141586..672ab67 100644
--- a/src/fst.cpp
+++ b/src/fst.cpp
@@ -863,18 +863,18 @@ void Transducer::store(FILE *file)
 
 static void read_node(FILE *file, Node *node, Node **p, Transducer *a) {
   char c;
-  fread(&c, sizeof(c), 1, file);
+  (void)!fread(&c, sizeof(c), 1, file);
   node->set_final(c);
 
   unsigned short n;
-  fread(&n, sizeof(n), 1, file);
+  (void)!fread(&n, sizeof(n), 1, file);
 
   for (int i = 0; i < n; i++) {
     Character lc, uc;
     unsigned int t;
-    fread(&lc, sizeof(lc), 1, file);
-    fread(&uc, sizeof(uc), 1, file);
-    fread(&t, sizeof(t), 1, file);
+    (void)!fread(&lc, sizeof(lc), 1, file);
+    (void)!fread(&uc, sizeof(uc), 1, file);
+    (void)!fread(&t, sizeof(t), 1, file);
     if (ferror(file))
       throw "Error encountered while reading transducer from file";
     if (p[t])
@@ -901,7 +901,7 @@ void Transducer::read_transducer_binary(FILE *file)
 
   vmark = deterministic = 0;
   unsigned int n;
-  fread(&n, sizeof(n), 1, file); // number of nodes
+  (void)!fread(&n, sizeof(n), 1, file); // number of nodes
   if (ferror(file))
     throw "Error encountered while reading transducer from file";
 
diff --git a/src/lowmem.h b/src/lowmem.h
index 7ff9440..3fed278 100644
--- a/src/lowmem.h
+++ b/src/lowmem.h
@@ -42,15 +42,15 @@ class LMNode {
 
   LMNode(long pos, FILE *lmafile) {
     fseek(lmafile, pos, SEEK_SET);
-    fread(&finalp, sizeof(finalp), 1, lmafile);
-    fread(&number_of_arcs, sizeof(number_of_arcs), 1, lmafile);
+    (void)!fread(&finalp, sizeof(finalp), 1, lmafile);
+    (void)!fread(&number_of_arcs, sizeof(number_of_arcs), 1, lmafile);
     arc = new LMArc[number_of_arcs];
     for (int i = 0; i < (int)number_of_arcs; i++) {
       Character lc, uc;
       unsigned int tpos;
-      fread(&lc, sizeof(lc), 1, lmafile);
-      fread(&uc, sizeof(uc), 1, lmafile);
-      fread(&tpos, sizeof(tpos), 1, lmafile);
+      (void)!fread(&lc, sizeof(lc), 1, lmafile);
+      (void)!fread(&uc, sizeof(uc), 1, lmafile);
+      (void)!fread(&tpos, sizeof(tpos), 1, lmafile);
       arc[i].label = Label(lc, uc);
       arc[i].tnodepos = tpos;
     }
diff --git a/src/utf8-scanner.ll b/src/utf8-scanner.ll
index 80d2774..c16c1c4 100644
--- a/src/utf8-scanner.ll
+++ b/src/utf8-scanner.ll
@@ -23,7 +23,7 @@
 using namespace SFST;
 
 #define MAX_INCLUDE_DEPTH 10
-  
+
 int Include_Stack_Ptr = 0;
 YY_BUFFER_STATE Include_Stack[MAX_INCLUDE_DEPTH];
 char *Name_Stack[MAX_INCLUDE_DEPTH];
@@ -34,9 +34,9 @@ char *FileName=NULL;
 
 bool UTF8=true;
 
-static void unmatched( char sym ) {
-  fprintf(stderr,"Warning: unmatched symbol \"%c\". You might want to quote it.\n", sym);
-}
+// static void unmatched( char sym ) {
+//   fprintf(stderr,"Warning: unmatched symbol \"%c\". You might want to quote it.\n", sym);
+//}
 
 static char *unquote(char *string, bool del_quote=true) {
   char *s=string, *result=string;
@@ -155,13 +155,13 @@ FN	[A-Za-z0-9._/\-*+]
 
 \<({C5}|\\.)*\>   { yylval.name = unquote(yytext,false); return SYMBOL; }
 
-\"<{FN}+>\" { 
+\"<{FN}+>\" {
                     yylval.value = fst_strdup(yytext+2);
 		    yylval.value[strlen(yylval.value)-2] = 0;
                     return STRING2;
                   }
 
-\"{FN}+\" { 
+\"{FN}+\" {
                     yylval.value = fst_strdup(yytext+1);
 		    yylval.value[strlen(yylval.value)-1] = 0;
                     return STRING;
@@ -171,7 +171,7 @@ FN	[A-Za-z0-9._/\-*+]
 \\[ \t]*([ \t]\%.*)?\r?\n { print_lineno(); /* ignored */ }
 \r?\n             { print_lineno(); return NEWLINE; }
 
-\\[0-9]+          { long l=atol(yytext+1); 
+\\[0-9]+          { long l=atol(yytext+1);
 		    if (l <= 1114112) { yylval.value=fst_strdup(int2utf8((unsigned)l)); return UTF8CHAR; }
 		    yyerror("invalid expression");
                   }