🔥 conditional_cast

include/spdlog/common.h

@@ -320,6 +320,20 @@ struct file_event_handlers
 };
 
 namespace details {
+
+// to avoid useless casts (see https://github.com/nlohmann/json/issues/2893#issuecomment-889152324)
+template<typename T, typename U, std::enable_if_t<!std::is_same<T, U>::value, int> = 0>
+constexpr T conditional_static_cast(U value)
+{
+    return static_cast<T>(value);
+}
+
+template<typename T, typename U, std::enable_if_t<std::is_same<T, U>::value, int> = 0>
+constexpr T conditional_static_cast(U value)
+{
+    return value;
+}
+
 // make_unique support for pre c++14
 
 #if __cplusplus >= 201402L // C++14 and beyond

include/spdlog/details/os-inl.h

@@ -405,9 +405,9 @@ SPDLOG_INLINE int pid() SPDLOG_NOEXCEPT
 {
 
 #ifdef _WIN32
-    return static_cast<int>(::GetCurrentProcessId());
+    return conditional_static_cast<int>(::GetCurrentProcessId());
 #else
-    return static_cast<int>(::getpid());
+    return conditional_static_cast<int>(::getpid());
 #endif
 }