Treat warnings as errors (#2490)

dlib/algs.h

@@ -370,7 +370,7 @@ namespace dlib
         and the fact that this has a different name (global swap has the same name as
         the member functions called swap) makes them compile right.
 
-        So this is a workaround but not too ugly of one.  But hopefully I get get
+        So this is a workaround but not too ugly of one.  But hopefully I can get
         rid of this in a few years.  So this function is already deprecated. 
 
         This also means you should NOT use this function in your own code unless

dlib/array2d/array2d_kernel.h

@@ -117,14 +117,16 @@ namespace dlib
         private:
 
             row(T* data_, long cols) : data(data_), nc_(cols) {}
+            row(row&& r) = default;
+            row& operator=(row&& r) = default;
 
-            T* data; 
-            long nc_;
+            T* data = nullptr;
+            long nc_ = 0;
 
 
             // restricted functions
-            row(){}
-            row& operator=(row&);
+            row(const row&) = delete;
+            row& operator=(const row&) = delete;
         };
 
         // -----------------------------------

dlib/bayes_utils/bayes_utils.h

@@ -1518,7 +1518,6 @@ namespace dlib
 
 
                 bool message_sent = true;
-                std::vector<unsigned long>::iterator iter;
                 while (message_sent)
                 {
                     message_sent = false;

dlib/crc32/crc32_kernel_1.h

@@ -26,10 +26,10 @@ namespace dlib
         // this is here for backwards compatibility with older versions of dlib.
         typedef crc32 kernel_1a;
 
-        inline crc32 (        
+        inline crc32 (
         );
 
-        inline crc32 (        
+        inline crc32 (
             const std::string& item
         );
 
@@ -65,10 +65,6 @@ namespace dlib
             crc32& item
         );
 
-        inline crc32& operator=(
-            const crc32&
-        );  
-
     private:
 
         unsigned long checksum;
@@ -147,7 +143,7 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     crc32::
-    crc32 (        
+    crc32 (
     )
     {
         checksum = 0xFFFFFFFF;
@@ -243,17 +239,6 @@ namespace dlib
         exchange(checksum,item.checksum);
     }
 
-// ----------------------------------------------------------------------------------------
-
-    crc32& crc32::
-    operator=(
-        const crc32& item
-    )
-    {
-        checksum = item.checksum;
-        return *this;
-    }
-
 // ----------------------------------------------------------------------------------------
 
 }

dlib/crc32/crc32_kernel_abstract.h

@@ -31,7 +31,7 @@ namespace dlib
                 - #*this is properly initialized
         !*/
 
-        crc32 (        
+        crc32 (
             const std::string& item
         );
         /*!

dlib/cuda/cpu_dlib.cpp

@@ -2479,7 +2479,7 @@ namespace dlib
             float* t = &output(0,0);
 
             // now fill in the Toeplitz output matrix for the n-th sample in data.  
-            size_t cnt = 0;
+            long cnt = 0;
             const long max_r = data.nr() + padding_y-(filter_nr-1);
             const long max_c = data.nc() + padding_x-(filter_nc-1);
             for (long r = -padding_y; r < max_r; r+=stride_y)

dlib/dnn/core.h

@@ -2259,7 +2259,7 @@ namespace dlib
         void back_propagate_error(
             const tensor& /*x*/,
             const tensor& /*gradient_input*/,
-            zero_gradients zero_grads = zero_gradients::yes
+            zero_gradients /*zero_grads*/ = zero_gradients::yes
         )
         {
             // nothing to do
@@ -3746,7 +3746,7 @@ namespace dlib
                 typename visitor
                 >
             static void visit(
-                net_type& net,
+                net_type&,
                 const add_tag_layer<tag_id,SUBNET>& next_net,
                 visitor&& v
             )
@@ -3760,7 +3760,7 @@ namespace dlib
                 typename visitor
                 >
             static void visit(
-                net_type& net,
+                net_type&,
                 add_tag_layer<tag_id,SUBNET>& next_net,
                 visitor&& v
             )

dlib/dnn/input.h

@@ -476,7 +476,6 @@ namespace dlib
         typedef matrix<T,NR,NC,MM,L> input_type;
 
         input() {}
-        input(const input&) {}
 
         template <typename mm>
         input(const input<array2d<T,mm>>&) {}
@@ -728,25 +727,25 @@ namespace dlib
 
         }
 
-        friend void serialize(const input& item, std::ostream& out)
+        friend void serialize(const input&, std::ostream& out)
         {
             serialize("input<array2d>", out);
         }
 
-        friend void deserialize(input& item, std::istream& in)
+        friend void deserialize(input&, std::istream& in)
         {
             std::string version;
             deserialize(version, in);
             if (version != "input<array2d>")
                 throw serialization_error("Unexpected version found while deserializing dlib::input.");
         }
-        friend std::ostream& operator<<(std::ostream& out, const input& item)
+        friend std::ostream& operator<<(std::ostream& out, const input&)
         {
             out << "input<array2d>";
             return out;
         }
 
-        friend void to_xml(const input& item, std::ostream& out)
+        friend void to_xml(const input&, std::ostream& out)
         {
             out << "<input/>";
         }

dlib/dnn/visitors.h

@@ -552,7 +552,7 @@ namespace dlib
             visitor_net_to_dot(std::ostream& out) : out(out) {}
 
             template <typename input_layer_type>
-            void operator()(size_t i, input_layer_type& l)
+            void operator()(size_t i, input_layer_type&)
             {
                 start_node(i, "input");
                 end_node();
@@ -609,7 +609,7 @@ namespace dlib
             }
 
             template <template <typename> class TAG, typename U>
-            void operator()(size_t i, const add_skip_layer<TAG, U>&)
+            void operator()(size_t, const add_skip_layer<TAG, U>&)
             {
                 const auto t = tag_id<TAG>::id;
                 from = tag_to_layer.at(t);
@@ -887,7 +887,7 @@ namespace dlib
             }
 
             template <template <typename> class... TAGS, typename U, typename E>
-            void operator()(size_t i, const add_layer<concat_<TAGS...>, U, E>& l)
+            void operator()(size_t i, const add_layer<concat_<TAGS...>, U, E>&)
             {
                 start_node(i, "concat");
                 end_node();
@@ -930,7 +930,7 @@ namespace dlib
             }
 
             template <typename T, typename U, typename E>
-            void operator()(size_t i, const add_layer<T, U, E>& l)
+            void operator()(size_t i, const add_layer<T, U, E>&)
             {
                 start_node(i, "unhandled layer");
                 update(i);

dlib/geometry/rectangle.h

@@ -750,7 +750,7 @@ namespace dlib
 
     // Circumvent what appears to be a bug in Visual Studio 2019's optimizer
     // (see: https://forum.juce.com/t/warning-in-the-lastest-vs2019/38267)
-#if defined (_MSVC_VER)
+#if defined (_MSC_VER)
 #pragma warning ( push )
 #pragma warning ( disable: 4723 )
 #endif
@@ -774,7 +774,7 @@ namespace dlib
             return centered_rect(rect, (long)std::round(rect.width()*scale), (long)std::round(rect.height()*scale));
         }
     }
-#if defined (_MSVC_VER)
+#if defined (_MSC_VER)
 #pragma warning ( pop )
 #endif
 

dlib/interfaces/map_pair.h

@@ -31,6 +31,9 @@ namespace dlib
         typedef T1 key_type;
         typedef T2 value_type;
 
+        map_pair() = default;
+        map_pair(const map_pair&) = default;
+
         virtual ~map_pair(
         )=0;
 

dlib/pixel.h

@@ -710,6 +710,12 @@ namespace dlib
         }
     // -----------------------------
 
+        // Apparently Visual Studio's optimizer complains about branches that would not be taken anyway.
+#if defined (_MSC_VER)
+#pragma warning ( push )
+#pragma warning ( disable: 4756 )
+#endif
+
         template < typename P1, typename P2 >
         typename enable_if_c<pixel_traits<P1>::grayscale && pixel_traits<P2>::grayscale>::type
         assign(P1& dest, const P2& src) 
@@ -728,6 +734,10 @@ namespace dlib
                 dest = pixel_traits<P1>::max();
         }
 
+#if defined (_MSC_VER)
+#pragma warning ( pop )
+#endif
+
     // -----------------------------
     // -----------------------------
     // -----------------------------

dlib/static_map/static_map_kernel_1.h

@@ -47,12 +47,12 @@ namespace dlib
                 - if (current_element_valid()) then
                     - element() == mp
         !*/
-        
+       
         class mpair : public map_pair<domain,range>
         {
         public:
-            const domain* d;
-            range* r;
+            const domain* d = nullptr;
+            range* r = nullptr;
 
             const domain& key( 
             ) const { return *d; }

dlib/svm/assignment_function.h

@@ -154,7 +154,7 @@ namespace dlib
             {
                 // max_cost_assignment() only works with integer matrices, so convert from
                 // double to integer.
-                const double scale = (std::numeric_limits<dlib::int64>::max()/1000)/max(abs(cost));
+                const double scale = static_cast<double>(std::numeric_limits<dlib::int64>::max())/1000/max(abs(cost));
                 matrix<dlib::int64> int_cost = matrix_cast<dlib::int64>(round(cost*scale));
                 assignment = max_cost_assignment(int_cost);
                 assignment.resize(lhs.size());

dlib/svm/function.h

@@ -43,15 +43,6 @@ namespace dlib
         decision_function (
         ) : b(0), kernel_function(K()) {}
 
-        decision_function (
-            const decision_function& d
-        ) : 
-            alpha(d.alpha), 
-            b(d.b),
-            kernel_function(d.kernel_function),
-            basis_vectors(d.basis_vectors) 
-        {}
-
         decision_function (
             const scalar_vector_type& alpha_,
             const scalar_type& b_,
@@ -137,14 +128,6 @@ namespace dlib
         probabilistic_function (
         ) : alpha(0), beta(0), decision_funct(function_type()) {}
 
-        probabilistic_function (
-            const probabilistic_function& d
-        ) : 
-            alpha(d.alpha),
-            beta(d.beta),
-            decision_funct(d.decision_funct)
-        {}
-
         probabilistic_function (
             const scalar_type a_,
             const scalar_type b_,
@@ -232,14 +215,6 @@ namespace dlib
             decision_funct(d.decision_funct)
         {}
 
-        probabilistic_decision_function (
-            const probabilistic_decision_function& d
-        ) : 
-            alpha(d.alpha),
-            beta(d.beta),
-            decision_funct(d.decision_funct)
-        {}
-
         probabilistic_decision_function (
             const scalar_type a_,
             const scalar_type b_,
@@ -353,16 +328,6 @@ namespace dlib
                 );
         }
 
-        distance_function (
-            const distance_function& d
-        ) : 
-            alpha(d.alpha), 
-            b(d.b),
-            kernel_function(d.kernel_function),
-            basis_vectors(d.basis_vectors) 
-        {
-        }
-
         distance_function (
             const scalar_vector_type& alpha_,
             const scalar_type& b_,
@@ -586,13 +551,6 @@ namespace dlib
         normalized_function (
         ){}
 
-        normalized_function (
-            const normalized_function& f
-        ) :
-            normalizer(f.normalizer),
-            function(f.function)
-        {}
-
         const std::vector<result_type> get_labels(
         ) const { return function.get_labels(); }
 
@@ -673,10 +631,6 @@ namespace dlib
         projection_function (
         ) {}
 
-        projection_function (
-            const projection_function& f
-        ) : weights(f.weights), kernel_function(f.kernel_function), basis_vectors(f.basis_vectors) {}
-
         projection_function (
             const scalar_matrix_type& weights_,
             const K& kernel_function_,

dlib/svm/function_abstract.h

@@ -64,14 +64,6 @@ namespace dlib
                 - #basis_vectors.nr() == 0
         !*/
 
-        decision_function (
-            const decision_function& f
-        );
-        /*!
-            ensures
-                - #*this is a copy of f
-        !*/
-
         decision_function (
             const scalar_vector_type& alpha_,
             const scalar_type& b_,
@@ -169,14 +161,6 @@ namespace dlib
                 - #decision_funct has its initial value
         !*/
 
-        probabilistic_function (
-            const probabilistic_function& f
-        );
-        /*!
-            ensures
-                - #*this is a copy of f
-        !*/
-
         probabilistic_function (
             const scalar_type a,
             const scalar_type b,
@@ -282,15 +266,7 @@ namespace dlib
         !*/
 
         probabilistic_decision_function (
-            const probabilistic_decision_function& f
-        );
-        /*!
-            ensures
-                - #*this is a copy of f
-        !*/
-
-        probabilistic_decision_function (
-            const probabilistic_function<decision_function<K> >& d
+            const probabilistic_function<decision_function<K> >& f
         );
         /*!
             ensures
@@ -445,17 +421,6 @@ namespace dlib
                     - #get_basis_vectors() == f.basis_vectors
         !*/
 
-        distance_function (
-            const distance_function& f
-        );
-        /*!
-            requires
-                - f is a valid distance_function.  In particular, this means that
-                  f.alpha.size() == f.basis_vectors.size()
-            ensures
-                - #*this is a copy of f
-        !*/
-
         distance_function (
             const scalar_vector_type& alpha,
             const scalar_type& squared_norm,
@@ -679,14 +644,6 @@ namespace dlib
                 - the members of this object have their default values
         !*/
 
-        normalized_function (
-            const normalized_function& f
-        );
-        /*!
-            ensures
-                - #*this is a copy of f
-        !*/
-
         normalized_function (
             const vector_normalizer<sample_type>& normalizer_,
             const function_type& funct 
@@ -791,14 +748,6 @@ namespace dlib
                 - #basis_vectors.size() == 0
         !*/
 
-        projection_function (
-            const projection_function& f
-        );
-        /*!
-            ensures
-                - #*this is a copy of f
-        !*/
-
         projection_function (
             const scalar_matrix_type& weights_,
             const K& kernel_function_,

dlib/svm/pegasos.h

@@ -655,7 +655,7 @@ namespace dlib
 
         trainer_type trainer;
         scalar_type min_learning_rate;
-        bool verbose;
+        bool verbose = true;
         bool use_cache;
         long cache_size;
 

dlib/svm/structural_svm_assignment_problem.h

@@ -247,7 +247,7 @@ namespace dlib
             {
                 // max_cost_assignment() only works with integer matrices, so convert from
                 // double to integer.
-                const double scale = (std::numeric_limits<dlib::int64>::max()/1000)/max(abs(cost));
+                const double scale = static_cast<double>(std::numeric_limits<dlib::int64>::max())/1000/max(abs(cost));
                 matrix<dlib::int64> int_cost = matrix_cast<dlib::int64>(round(cost*scale));
                 assignment = max_cost_assignment(int_cost);
                 assignment.resize(samples[idx].first.size());

dlib/test/CMakeLists.txt

@@ -166,13 +166,22 @@ set (tests
 # cmake that they are part of our target (which is the executable named dtest)
 ADD_EXECUTABLE(${target_name} main.cpp tester.cpp ${tests})
 
-# Turn on all warnings when using gcc.
 if (CMAKE_COMPILER_IS_GNUCXX)
-   add_definitions("-W -Wall")
+   # Turn on all warnings, and treat them as errors.
+   add_definitions("-W -Wall -Wextra -Werror")
    # I don't care about unused testing functions though.  I like to keep them
    # around.  Don't warn about it.
    add_definitions("-Wno-unused-function")
    add_definitions("-Wno-strict-overflow")
+   add_definitions("-Wno-maybe-uninitialized")
+elseif (MSVC)
+   # Treat warnings as errors.
+   add_definitions("/WX")
+else() # basically Clang
+   # Treat warnings as errors, but do not turn on all warnings.
+   add_definitions("-W -Werror")
+   # This is for the comment in face_detection_ex.cpp that says "faces/*.jpg"
+   add_definitions("-Wno-comment")
 endif()
 
 
@@ -181,6 +190,12 @@ TARGET_LINK_LIBRARIES(${target_name} dlib::dlib )
 
 if (NOT DLIB_NO_GUI_SUPPORT)
    add_subdirectory(gui)
-   add_subdirectory(examples)
    add_subdirectory(tools)
+
+   if (CMAKE_COMPILER_IS_GNUCXX)
+      # The tutorials set some variables that are not used.
+      add_definitions("-Wno-unused-but-set-variable")
+   endif()
+
+   add_subdirectory(examples)
 endif()

dlib/test/compress_stream.cpp

@@ -75,7 +75,7 @@ namespace
             bool detected_error = false;
             try {
                 test.decompress(sin,sout);
-            } catch ( typename cs::decompression_error& e )
+            } catch ( typename cs::decompression_error& )
             {
                 detected_error = true;
                 ++count;