fix the multiple definitions of lexical casts methods (#1281) (#1283)

hardware_interface/CMakeLists.txt

@@ -27,6 +27,7 @@ add_library(hardware_interface SHARED
   src/resource_manager.cpp
   src/sensor.cpp
   src/system.cpp
+  src/lexical_casts.cpp
 )
 target_compile_features(hardware_interface PUBLIC cxx_std_17)
 target_include_directories(hardware_interface PUBLIC

hardware_interface/include/hardware_interface/lexical_casts.hpp

@@ -28,24 +28,9 @@ namespace hardware_interface
  * from
  https://github.com/ros-planning/srdfdom/blob/ad17b8d25812f752c397a6011cec64aeff090c46/src/model.cpp#L53
 */
-double stod(const std::string & s)
-{
-  // convert from string using no locale
-  std::istringstream stream(s);
-  stream.imbue(std::locale::classic());
-  double result;
-  stream >> result;
-  if (stream.fail() || !stream.eof())
-  {
-    throw std::invalid_argument("Failed converting string to real number");
-  }
-  return result;
-}
+double stod(const std::string & s);
 
-bool parse_bool(const std::string & bool_string)
-{
-  return bool_string == "true" || bool_string == "True";
-}
+bool parse_bool(const std::string & bool_string);
 
 }  // namespace hardware_interface
 

hardware_interface/src/lexical_casts.cpp

@@ -0,0 +1,37 @@
+// Copyright 2024 ros2_control Development Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "hardware_interface/lexical_casts.hpp"
+
+namespace hardware_interface
+{
+double stod(const std::string & s)
+{
+  // convert from string using no locale
+  std::istringstream stream(s);
+  stream.imbue(std::locale::classic());
+  double result;
+  stream >> result;
+  if (stream.fail() || !stream.eof())
+  {
+    throw std::invalid_argument("Failed converting string to real number");
+  }
+  return result;
+}
+
+bool parse_bool(const std::string & bool_string)
+{
+  return bool_string == "true" || bool_string == "True";
+}
+}  // namespace hardware_interface