diff --git a/test/compare_parsers/ansic.y b/test/compare_parsers/ansic.y
index 0e18a69..4f8ab96 100644
--- a/test/compare_parsers/ansic.y
+++ b/test/compare_parsers/ansic.y
@@ -26,6 +26,7 @@
 
 %{
 #define YYSTYPE string_t
+int yyerror(char* s);
 %}
 
 %token IDENTIFIER CONSTANT STRING_LITERAL SIZEOF
@@ -471,8 +472,7 @@ identifier
 extern int column;
 extern int line;
 
-yyerror(s)
-char *s;
+int yyerror(char* s)
 {
    fprintf (stderr, "syntax error line - %d, column - %d\n", line, column + 1);
 }
diff --git a/test/compare_parsers/test_yaep.c b/test/compare_parsers/test_yaep.c
index 2ce2171..698db37 100644
--- a/test/compare_parsers/test_yaep.c
+++ b/test/compare_parsers/test_yaep.c
@@ -827,7 +827,7 @@ static const char *description =
 #include <unistd.h>
 #endif
 
-main (int argc, char **argv)
+int main (int argc, char **argv)
 {
   ticker_t t;
   int code, ambiguous_p;
diff --git a/test/compare_parsers/test_yyparse.c b/test/compare_parsers/test_yyparse.c
index b50b06e..c563ed0 100644
--- a/test/compare_parsers/test_yyparse.c
+++ b/test/compare_parsers/test_yyparse.c
@@ -40,6 +40,7 @@ static int level = 0;
 
 #include "test_common.c"
 
+extern int get_lex (void);
 #define yylex get_lex
 #include "y.tab.c"
 #undef yylex
@@ -100,7 +101,7 @@ static void store_lexs( YaepAllocator * alloc ) {
   }
 }
 
-main()
+int main()
 {
   ticker_t t;
   int code;