Add option for dll-local registry on Linux

CMakeLists.txt

@@ -56,6 +56,7 @@ endif ()
 # build shared option
 if(NOT WIN32)
     option(SPDLOG_BUILD_SHARED "Build shared library" OFF)
+    option(SPDLOG_DLL_LOCAL_REGISTRY "If enabled, the logger registry will not be shared between shared objects" OFF)
 endif()
 
 # example options
@@ -122,6 +123,10 @@ else()
     add_library(spdlog STATIC ${SPDLOG_SRCS} ${SPDLOG_ALL_HEADERS})
 endif()
 
+if (SPDLOG_DLL_LOCAL_REGISTRY)
+    target_compile_definitions(spdlog PUBLIC SPDLOG_DLL_LOCAL_REGISTRY)
+endif()
+
 add_library(spdlog::spdlog ALIAS spdlog)
 
 target_compile_definitions(spdlog PUBLIC SPDLOG_COMPILED_LIB)

include/spdlog/common.h

@@ -54,6 +54,12 @@
 #define SPDLOG_DEPRECATED
 #endif
 
+#if defined(SPDLOG_DLL_LOCAL_REGISTRY) && (defined(__GNUC__) || defined(__clang__))
+#define SPDLOG_REGISTRY_ATTRIBUTES __attribute__((visibility("hidden")))
+#else
+#define SPDLOG_REGISTRY_ATTRIBUTES
+#endif
+
 // disable thread local on msvc 2013
 #ifndef SPDLOG_NO_TLS
 #if (defined(_MSC_VER) && (_MSC_VER < 1900)) || defined(__cplusplus_winrt)

include/spdlog/details/registry.h

@@ -24,7 +24,7 @@ namespace details {
 class thread_pool;
 class periodic_worker;
 
-class registry
+class SPDLOG_REGISTRY_ATTRIBUTES registry
 {
 public:
     registry(const registry &) = delete;