Allow kdlpp to be built as shared library (#3)

bindings/cpp/CMakeLists.txt

@@ -40,11 +40,19 @@ if(BUILD_KDLPP)
         src/kdlpp.cpp
     )
 
-    add_library(kdlpp STATIC ${KDLPP_CXX_SOURCES})
+    add_library(kdlpp ${KDLPP_CXX_SOURCES})
+
     target_compile_options(kdlpp PRIVATE ${KDL_COMPILE_OPTIONS})
+    target_compile_definitions(kdlpp PRIVATE BUILDING_KDLPP=1)
+
     target_include_directories(kdlpp PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
     target_link_libraries(kdlpp PUBLIC kdl)
     target_compile_features(kdlpp PUBLIC cxx_std_20)
+
+    if(NOT BUILD_SHARED_LIBS)
+        target_compile_definitions(kdlpp PUBLIC KDLPP_STATIC_LIB=1)
+    endif()
+
     install(TARGETS kdlpp COMPONENT libkdlpp)
     install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/include/kdlpp.h TYPE INCLUDE COMPONENT libkdlpp)
 

bindings/cpp/include/kdlpp.h

@@ -1,6 +1,20 @@
 #ifndef KDLPP_H_
 #define KDLPP_H_
 
+#if defined(_WIN32)
+#    if defined(KDLPP_STATIC_LIB)
+#        define KDLPP_EXPORT
+#    elif defined(BUILDING_KDLPP)
+#        define KDLPP_EXPORT __declspec(dllexport)
+#    else
+#        define KDLPP_EXPORT __declspec(dllimport)
+#    endif
+#elif defined(__GNUC__) && __GNUC__ >= 4
+#    define KDLPP_EXPORT __attribute__((visibility("default")))
+#else
+#    define KDLPP_EXPORT
+#endif
+
 #include <functional>
 #include <map>
 #include <optional>
@@ -30,7 +44,7 @@ class TypeError : public std::exception {
 };
 
 // Exception thrown on regular KDL parsing errors
-class ParseError : public std::exception {
+class KDLPP_EXPORT ParseError : public std::exception {
     std::string m_msg;
 public:
     ParseError(kdl_str const& msg);
@@ -57,7 +71,7 @@ enum NumberRepresentation {
 
 // A KDL number: could be a long long, a double, or a string
 // Analogous to kdl_number
-class Number {
+class KDLPP_EXPORT Number {
     std::variant<long long, double, std::u8string> m_value;
 
 public:
@@ -138,7 +152,7 @@ enum class Type {
 
 // A KDL value, possibly including a type annotation
 // Analogous to kdl_value
-class Value : public HasTypeAnnotation {
+class KDLPP_EXPORT Value : public HasTypeAnnotation {
     std::variant<std::monostate, bool, Number, std::u8string> m_value;
 
 public:
@@ -311,7 +325,7 @@ class Node : public HasTypeAnnotation {
 };
 
 // A KDL document - consisting of several nodes.
-class Document {
+class KDLPP_EXPORT Document {
     std::vector<Node> m_nodes;
 
 public:
@@ -338,7 +352,7 @@ class Document {
 };
 
 // Load a KDL document from string
-Document parse(std::u8string_view kdl_text);
+KDLPP_EXPORT Document parse(std::u8string_view kdl_text);
 
 } // namespace kdl
 

bindings/cpp/tests/CMakeLists.txt

@@ -6,7 +6,7 @@ target_link_libraries(kdlpp_test kdlpp test_util)
 add_test(kdlpp_test kdlpp_test)
 
 if (WIN32 AND BUILD_SHARED_LIBS)
-    # Copy kdl.dll to the test folder so that the tests work
+    # Copy kdl.dll and kdlpp.dll to the test folder so that the tests work
     add_custom_command(TARGET kdlpp_test POST_BUILD
-        COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:kdl> $<TARGET_FILE_DIR:kdlpp_test>)
+        COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:kdl> $<TARGET_FILE:kdlpp> $<TARGET_FILE_DIR:kdlpp_test>)
 endif()

doc/index.rst

@@ -89,16 +89,17 @@ of the ``DESTDIR`` environment variable).
 Dynamic vs static library
 ^^^^^^^^^^^^^^^^^^^^^^^^^
 
-The ckdl C library ``libkdl`` supports both dynamic linking and static linking. Which option
-you want to choose depends on your situation: When using C, C++, or a similar language, static
-libraries can be easier to work with, while when using a dynamic runtime a dynamic library
-may be your best bet (Python's ctypes and .NET's P/Invoke are examples of technologies that
-as good as require the use of a dynamic library).
+The ckdl C library ``libkdl`` and the C++ bindings ``libkdlpp`` support both dynamic linking
+and static linking. Which option you want to choose depends on your situation: When using C,
+C++, or a similar language, static libraries can be easier to work with, while when using a
+dynamic runtime a dynamic library may be your best bet (Python's ctypes and .NET's P/Invoke
+are examples of technologies that as good as require the use of a dynamic library).
 
 .. attention::
 
     On **Windows**, if you're using the static library, and not the DLL, you must define the
-    macro ``KDL_STATIC_LIB`` before including the ckdl headers, or you'll get linking errors.
+    macro ``KDL_STATIC_LIB`` before including the ckdl headers, and ``KDLPP_STATIC_LIB``
+    before including the kdlpp header, or you'll get linking errors.
 
     On UNIX, this is not required, but it can't hurt in portable applications and libraries.