Build fix: missing type traits on gcc < 5.0

[lttng-tools.git] / src / common / macros.hpp

diff --git a/src/common/macros.hpp b/src/common/macros.hpp
index b734652eea9ea89218d7e798edabed46fe272e73..a4ff6504d078807056330c4fd8f3e25b3a05f2ad 100644 (file)
--- a/src/common/macros.hpp
+++ b/src/common/macros.hpp
@@ -63,7 +63,19 @@ void *zmalloc_internal(size_t size)
 template <typename T>
 struct can_malloc
 {
+       /*
+        * gcc versions before 5.0 lack some type traits defined in C++11.
+        * Since in this instance we use the trait to prevent misuses
+        * of malloc (and statically assert) and not to generate different
+        * code based on this property, simply set value to true and allow
+        * the code to compile. Anyone using a contemporary compiler will
+        * catch the error.
+        */
+#if __GNUG__ && __GNUC__ < 5
+       static constexpr bool value = true;
+#else
        static constexpr bool value = std::is_trivially_constructible<T>::value;
+#endif
 };
 
 /*
@@ -138,7 +150,19 @@ T *malloc(size_t size)
 template<typename T>
 struct can_free
 {
+       /*
+        * gcc versions before 5.0 lack some type traits defined in C++11.
+        * Since in this instance we use the trait to prevent misuses
+        * of free (and statically assert) and not to generate different
+        * code based on this property, simply set value to true and allow
+        * the code to compile. Anyone using a contemporary compiler will
+        * catch the error.
+        */
+#if __GNUG__ && __GNUC__ < 5
+       static constexpr bool value = true;
+#else
        static constexpr bool value = std::is_trivially_destructible<T>::value || std::is_void<T>::value;
+#endif
 };
 
 template<typename T, typename = typename std::enable_if<!can_free<T>::value>::type>
@@ -156,7 +180,19 @@ void *memset(T *s, int c, size_t n) = delete;
 template<typename T>
 struct can_memcpy
 {
+       /*
+        * gcc versions before 5.0 lack some type traits defined in C++11.
+        * Since in this instance we use the trait to prevent misuses
+        * of memcpy (and statically assert) and not to generate different
+        * code based on this property, simply set value to true and allow
+        * the code to compile. Anyone using a contemporary compiler will
+        * catch the error.
+        */
+#if __GNUG__ && __GNUC__ < 5
+       static constexpr bool value = true;
+#else
        static constexpr bool value = std::is_trivially_copyable<T>::value;
+#endif
 };
 
 template <typename T, typename U,
@@ -167,7 +203,19 @@ void *memcpy(T *d, const U *s, size_t n) = delete;
 template<typename T>
 struct can_memmove
 {
+       /*
+        * gcc versions before 5.0 lack some type traits defined in C++11.
+        * Since in this instance we use the trait to prevent misuses
+        * of memmove (and statically assert) and not to generate different
+        * code based on this property, simply set value to true and allow
+        * the code to compile. Anyone using a contemporary compiler will
+        * catch the error.
+        */
+#if __GNUG__ && __GNUC__ < 5
+       static constexpr bool value = true;
+#else
        static constexpr bool value = std::is_trivially_copyable<T>::value;
+#endif
 };
 
 template <typename T, typename U,