external renderer: Rename FUNC_DECL to EXPORTED_FUNC_DECL to show that it also exports a function

* Add target parameters to compile all symbols invisible to the outside by default.
* Edit FUNC_DECL() macro to set attribute that exports the function

include/gds-render/output-renderers/external-renderer-interfaces.h

@@ -13,6 +13,11 @@
  * @{
  */
 
+/**
+ * @brief This define is used to export a function from a shared object
+ */
+#define EXPORT_FUNC __attribute__((visibility("default")))
+
 /**
  * @brief Function name expected to be found in external library for rendering.
  *
@@ -37,14 +42,15 @@
  *
  * The pure presence of this symbol name causes forking. The content of this variable is don't care.
  * @note Use this if you mess with the internal structures of gds-render
- *
  */
 #define EXTERNAL_LIBRARY_FORK_REQUEST exported_fork_request
 
 /**
- * @brief Define for declaring the exported functions
+ * @brief Define for declaring the exported functions.
+ *
+ * This not only helps with the declaration but also makes the symbols visible, so they can be called form outside the library
  */
-#define FUNC_DECL(FUNC) FUNC
+#define EXPORTED_FUNC_DECL(FUNC) EXPORT_FUNC FUNC
 
 /** @} */
 

plugins/plugin-example/CMakeLists.txt

@@ -10,3 +10,5 @@ link_libraries(${PYTHON_LDFLAGS} version)
 
 add_library(${PROJECT_NAME} SHARED EXCLUDE_FROM_ALL ${SOURCES})
 add_dependencies(${PROJECT_NAME} version)
+set_target_properties(${PROJECT_NAME} PROPERTIES C_VISIBILITY_PRESET hidden)
+set_target_properties(${PROJECT_NAME} PROPERTIES CXX_VISIBILITY_PRESET hidden)

plugins/plugin-example/src/plugin-main.c

@@ -31,7 +31,7 @@
 #include <gds-render/gds-utils/gds-types.h>
 #include <gds-render/output-renderers/external-renderer-interfaces.h>
 
-int FUNC_DECL(EXTERNAL_LIBRARY_RENDER_FUNCTION)(struct gds_cell *toplevel, GList *layer_info_list, const char *output_file_name, double scale)
+int EXPORTED_FUNC_DECL(EXTERNAL_LIBRARY_RENDER_FUNCTION)(struct gds_cell *toplevel, GList *layer_info_list, const char *output_file_name, double scale)
 {
 	if (!toplevel)
 		return -1000;
@@ -40,7 +40,7 @@ int FUNC_DECL(EXTERNAL_LIBRARY_RENDER_FUNCTION)(struct gds_cell *toplevel, GList
 	return 0;
 }
 
-int FUNC_DECL(EXTERNAL_LIBRARY_INIT_FUNCTION)(const char *params, const char *version)
+int EXPORTED_FUNC_DECL(EXTERNAL_LIBRARY_INIT_FUNCTION)(const char *params, const char *version)
 {
 	printf("Init with params: %s\ngds-render version: %s\n", params, version);
 	return 0;