Open62541pp Linker error when compiling on windows with dynamic linkage

[pemartin2]

Hi @lukasberbuer, another windows specific issue :-)

Introduced with 5357ee9, reproducible with v0.13.0

Building unresolved external symbol UA_VariableAttributes_default (and similar)

Steps to reproduce

• Windows OS
• Checkout version 5357ee9 of this repo (probably master or v0.13.0 will also do but not tested)
• Compile with dev configuration with modified BUILD_SHARED_LIBS": "ON"
• To have a simplified case: In tests\CMakeList.txt add_executable comment out all tests except Server.cpp (and main.cpp)
• --> Compilation results in unresolved external symbol UA_VariableAttributes_default

Workarounds:

• Change the include order either by setting cmake variable UA_ENABLE_AMALGAMATION
• Or in tests\Server.cpp just add a #include <open62541/server_config_default.h> above the open62541pp includes. Probably open62541/server.h is enough, forgot to test this.

Solution (not sure if it's the best and cleanest one):

In include\open62541pp\types instead of

#ifndef UA_DEFAULT_ATTRIBUTES_DEFINED
#define UA_DEFAULT_ATTRIBUTES_DEFINED
extern "C" const UA_VariableAttributes UA_VariableAttributes_default;
extern "C" const UA_VariableTypeAttributes UA_VariableTypeAttributes_default;
extern "C" const UA_MethodAttributes UA_MethodAttributes_default;
extern "C" const UA_ObjectAttributes UA_ObjectAttributes_default;
extern "C" const UA_ObjectTypeAttributes UA_ObjectTypeAttributes_default;
extern "C" const UA_ReferenceTypeAttributes UA_ReferenceTypeAttributes_default;
extern "C" const UA_DataTypeAttributes UA_DataTypeAttributes_default;
extern "C" const UA_ViewAttributes UA_ViewAttributes_default;
#endif

simply add the open62541 header #include "open62541/server.h" instead. This results in dllexport in open62541 and dllimport in open62541pp and the user's code.
I did not think too much about it but did not find a way to only declare the xxx_default parameters because this will collide with open62541\server.h.

[lukasberbuer]

Thanks again for catching bugs 😊

I updated the CI pipeline to both build static and shared libraries with Windows, Linux, macOS and different compilers: #288
And indeed the error revealed itself: https://github.com/open62541pp/open62541pp/actions/runs/9233973823/job/25407044441

Fix coming soon

[lukasberbuer]

@pemartin2, can you please verify the fix?

[pemartin2]

@lukasberbuer. Confirmed that the fix worked.