diff --git a/cppcms/cache_interface.h b/cppcms/cache_interface.h
index a5c6ae2..356e1fb 100644
--- a/cppcms/cache_interface.h
+++ b/cppcms/cache_interface.h
@@ -342,7 +342,7 @@ namespace cppcms {
 		booster::intrusive_ptr<impl::base_cache> cache_module_;
 
 		uint32_t page_compression_used_ : 1;
-		uint32_t reserved : 31;
+		CPPCMS_UNUSED_MEMBER uint32_t reserved : 31;
 	};
 
 
diff --git a/cppcms/defs.h b/cppcms/defs.h
index 8363079..8dfd6b8 100644
--- a/cppcms/defs.h
+++ b/cppcms/defs.h
@@ -45,4 +45,17 @@
 #define CPPCMS_DEPRECATED
 #endif
 
+#if defined __GNUC__ || defined __clang__ 
+#define CPPCMS_UNUSED __attribute__((unused))
+#else
+#define CPPCMS_UNUSED
+#endif
+
+#if defined __clang__ 
+#define CPPCMS_UNUSED_MEMBER __attribute__((unused))
+#else
+#define CPPCMS_UNUSED_MEMBER
+#endif
+
+
 #endif /// CPPCMS_DEFS_H
diff --git a/cppcms/form.h b/cppcms/form.h
index d6f42ca..33e5a6b 100644
--- a/cppcms/form.h
+++ b/cppcms/form.h
@@ -153,8 +153,8 @@ namespace cppcms {
 		uint32_t html_list_type_;
 		uint32_t widget_part_type_;
 		std::ostream *output_;
-		uint32_t reserved_1;
-		uint32_t reserved_2;
+		CPPCMS_UNUSED_MEMBER uint32_t reserved_1;
+		CPPCMS_UNUSED_MEMBER uint32_t reserved_2;
 		struct _data;
 		booster::hold_ptr<_data> d;
 
@@ -703,7 +703,7 @@ namespace cppcms {
 			uint32_t has_message_ : 1;
 			uint32_t has_error_ : 1;
 			uint32_t has_help_ : 1;
-			uint32_t reserverd_ : 24;
+			CPPCMS_UNUSED_MEMBER uint32_t reserverd_ : 24;
 
 			struct _data;
 			booster::hold_ptr<_data> d;
@@ -1324,7 +1324,7 @@ namespace cppcms {
 				uint32_t selected : 1;
 				uint32_t need_translation : 1;
 				uint32_t original_select : 1;
-				uint32_t reserved : 29;
+				CPPCMS_UNUSED_MEMBER uint32_t reserved : 29;
 				std::string id;
 				std::string str_option;
 				locale::message tr_option;
@@ -1411,7 +1411,7 @@ namespace cppcms {
 				~element();
 
 				uint32_t need_translation : 1;
-				uint32_t reserved : 31;
+				CPPCMS_UNUSED_MEMBER uint32_t reserved : 31;
 				std::string id;
 				std::string str_option;
 				locale::message tr_option;
@@ -1432,7 +1432,7 @@ namespace cppcms {
 			int default_selected_;
 
 			uint32_t non_empty_ : 1;
-			uint32_t reserverd  : 32;
+			CPPCMS_UNUSED_MEMBER uint32_t reserverd  : 32;
 		};
 
 		///
@@ -1474,7 +1474,7 @@ namespace cppcms {
 
 		private:
 			uint32_t vertical_ : 1;
-			uint32_t reserved_ : 31;
+			CPPCMS_UNUSED_MEMBER uint32_t reserved_ : 31;
 
 			struct _data;
 			booster::hold_ptr<_data> d;
@@ -1573,7 +1573,7 @@ namespace cppcms {
 
 			uint32_t check_charset_ : 1;
 			uint32_t check_non_empty_ : 1;
-			uint32_t reserved_ : 30;
+			CPPCMS_UNUSED_MEMBER uint32_t reserved_ : 30;
 
 			booster::shared_ptr<http::file> file_;
 
diff --git a/cppcms/http_content_filter.h b/cppcms/http_content_filter.h
index 73b79b5..f28c8f7 100644
--- a/cppcms/http_content_filter.h
+++ b/cppcms/http_content_filter.h
@@ -17,7 +17,7 @@
 namespace cppcms {
 
 namespace impl {
-	class cached_settings;
+	struct cached_settings;
 }
 
 namespace http {
diff --git a/cppcms/http_cookie.h b/cppcms/http_cookie.h
index 315b7ff..627c43e 100644
--- a/cppcms/http_cookie.h
+++ b/cppcms/http_cookie.h
@@ -165,7 +165,7 @@ private:
 	uint32_t secure_	: 1;
 	uint32_t has_age_	: 1;
 	uint32_t has_expiration_: 1;
-	uint32_t reserved_	: 29;
+	CPPCMS_UNUSED_MEMBER uint32_t reserved_	: 29;
 };
 
 
diff --git a/private/basic_allocator.h b/private/basic_allocator.h
index d1ec2ed..96c9924 100644
--- a/private/basic_allocator.h
+++ b/private/basic_allocator.h
@@ -69,7 +69,7 @@ public :
 	{
 		return true;
 	}
-	bool operator!=(basic_allocator const& a) const
+	bool operator!=(basic_allocator const&) const
 	{
 		return false;
 	}
diff --git a/private/buddy_allocator.h b/private/buddy_allocator.h
index ba88477..a0628f6 100644
--- a/private/buddy_allocator.h
+++ b/private/buddy_allocator.h
@@ -8,6 +8,7 @@
 #ifndef CPPCMS_PRIVATE_BUDDY_ALLOCATOR_H
 #define CPPCMS_PRIVATE_BUDDY_ALLOCATOR_H
 
+#include <cppcms/defs.h>
 #include <stddef.h>
 #include <assert.h>
 #include <memory.h>
@@ -314,7 +315,7 @@ private:
 	page *free_list_[sizeof(void*)*8];	// 16 always
 	size_t memory_size_;	
 	int max_bit_size_; // at least sizeof(size_t)	
-	size_t padding_for_alignment_[2]; 
+	CPPCMS_UNUSED_MEMBER size_t padding_for_alignment_[2]; 
 };
 } // impl
 } // cppcms
diff --git a/private/session_posix_file_storage.h b/private/session_posix_file_storage.h
index d7142e6..f5e2c75 100644
--- a/private/session_posix_file_storage.h
+++ b/private/session_posix_file_storage.h
@@ -29,7 +29,7 @@ namespace sessions {
 		virtual void remove(std::string const &sid);
 		virtual bool is_blocking();
 	private:
-		struct locked_file;
+		class locked_file;
 		struct _data;
 		bool read_timestamp(int fd);
 		bool read_from_file(int fd,time_t &timeout,std::string &data);
@@ -54,7 +54,7 @@ namespace sessions {
 		std::vector<pthread_mutex_t> mutexes_;
 
 		// friends 
-		friend struct locked_file;
+		friend class locked_file;
 		friend class session_file_storage_factory;
 	};
 
diff --git a/tests/pool_test.cpp b/tests/pool_test.cpp
index a0e685e..99e7190 100644
--- a/tests/pool_test.cpp
+++ b/tests/pool_test.cpp
@@ -214,8 +214,7 @@ public:
 	};
 	sender(cppcms::service &srv,pools *p) :
 		cppcms::application(srv),
-		pools_(p),
-		first_time_(true)
+		pools_(p)
 	{
 	}
 
@@ -265,7 +264,6 @@ public:
 	}
 private:
 	pools *pools_;
-	bool first_time_;
 };
 
 int main(int argc,char **argv)