diff --git a/CMakeLists.txt b/CMakeLists.txt
index fa44c87..8dbaa4d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,7 +4,7 @@ cmake_minimum_required(VERSION 3.13.4 FATAL_ERROR)
 # ======================================================================================================================
 
 # project
-project(Modbus_TCP_client_shm LANGUAGES CXX VERSION 0.0.1)
+project(Modbus_TCP_client_shm LANGUAGES CXX VERSION 1.0.0)
 
 # settings
 set(Target "Modbus_TCP_client_shm")    # Executable name (without file extension!)
@@ -24,8 +24,6 @@ option(OPTIMIZE_FOR_ARCHITECTURE "enable optimizations for specified architectur
 option(LTO_ENABLED "enable interprocedural and link time optimizations" ON)
 option(COMPILER_EXTENSIONS "enable compiler specific C++ extensions" OFF)
 
-
-
 # ======================================================================================================================
 # ======================================================================================================================
 
@@ -55,6 +53,10 @@ set_target_properties(${Target} PROPERTIES
         CXX_EXTENSIONS ${COMPILER_EXTENSIONS}
     )
 
+# project version and name
+target_compile_definitions(${Target} PUBLIC "PROJECT_VERSION=\"${CMAKE_PROJECT_VERSION}\"")
+target_compile_definitions(${Target} PUBLIC "PROJECT_NAME=\"${CMAKE_PROJECT_NAME}\"")
+
 # options that are valid for gcc and clang
 function(commonopts)
     # more debugging information
diff --git a/src/main.cpp b/src/main.cpp
index 84aba3a..5b02b03 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -81,7 +81,9 @@ int main(int argc, char **argv) {
                          ("r,reconnect",
                           "do not terminate if Master disconnects.")
                          ("h,help",
-                          "print usage");
+                          "print usage")
+                         ("version",
+                          "print version information");
     // clang-format on
 
     // parse arguments
@@ -135,6 +137,12 @@ int main(int argc, char **argv) {
         exit(EX_OK);
     }
 
+    // print usage
+    if (args.count("version")) {
+        std::cout << PROJECT_NAME << ' ' << PROJECT_VERSION << std::endl;
+        exit(EX_OK);
+    }
+
     // check arguments
     if (args["do-registers"].as<std::size_t>() > 0x10000) {
         std::cerr << "to many do_registers (maximum: 65536)." << std::endl;
diff --git a/src/modbus_shm.cpp b/src/modbus_shm.cpp
index 291c704..53df5b0 100644
--- a/src/modbus_shm.cpp
+++ b/src/modbus_shm.cpp
@@ -43,7 +43,7 @@ Shm_Mapping::Shm_Mapping(std::size_t        nb_bits,
     shm_data[AI].name = prefix + "AI";
 
     // create and map shm objects
-    for (std::size_t i = 0; i < reg_index_t::__SIZE__; ++i) {
+    for (std::size_t i = 0; i < reg_index_t::REG_COUNT; ++i) {
         auto &shm = shm_data[i];
 
         // create shm object
@@ -76,7 +76,7 @@ Shm_Mapping::Shm_Mapping(std::size_t        nb_bits,
 
 Shm_Mapping::~Shm_Mapping() {
     // unmap and delete shm objects
-    for (std::size_t i = 0; i < reg_index_t::__SIZE__; ++i) {
+    for (std::size_t i = 0; i < reg_index_t::REG_COUNT; ++i) {
         auto &shm = shm_data[i];
         if (shm.addr) {
             if (munmap(shm.addr, shm.size)) { perror(("Failed to unmap shared memory '" + shm.name + '\'').c_str()); }
diff --git a/src/modbus_shm.hpp b/src/modbus_shm.hpp
index 5c49fc4..4e2e3d7 100644
--- a/src/modbus_shm.hpp
+++ b/src/modbus_shm.hpp
@@ -14,7 +14,7 @@ namespace shm {
  */
 class Shm_Mapping {
 private:
-    enum reg_index_t : std::size_t { DO, DI, AO, AI, __SIZE__ };
+    enum reg_index_t : std::size_t { DO, DI, AO, AI, REG_COUNT };
 
     //! data for a shared memory object
     struct shm_data_t {
@@ -28,7 +28,7 @@ class Shm_Mapping {
     modbus_mapping_t mapping {};
 
     //! info for all shared memory objects
-    std::array<shm_data_t, reg_index_t::__SIZE__> shm_data;
+    std::array<shm_data_t, reg_index_t::REG_COUNT> shm_data;
 
 public:
     /*! \brief creates a new modbus_mapping_t. Like modbus_mapping_new(), but creates shared memory objects to store its