Calling DLL Functions under a namespace in RAD Studio - dll

Question

I'm new to using RAD Studio as I currently have to use it for this current project. What I am trying to do is call functions defined in a DLL file which I generated in Visual Studio in a RAD Studio C++ project .
Following the advice from this question below
Using Visual Studio DLL in Embarcadero RAD Studio XE?
I have converted the C++ DLL file I have generated from Visual Studio to a supported file for RAD studio using their command:
mkexp pub-sub-sample.a pub-sub-sample.dll
I can verify that my functions have been exported as I did the command dump.
Turbo Dump Version 6.5.4.0 Copyright (c) 1988-2016 Embarcadero Technologies, Inc.
Display of File pub-sub-sample.dll
EXPORT ord:0001='?DisconnectCallback#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##V?$shared_ptr#VDisconnectCallbackContextData#awsiotsdk###6##Z'
EXPORT ord:0002='?GetCurrentPath#ConfigCommon#awsiotsdk##SA?AV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##XZ'
EXPORT ord:0003='?InitializeCommon#ConfigCommon#awsiotsdk##SA?AW4ResponseCode#2#AEBV?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std###Z'
EXPORT ord:0004='?InitializeTLS#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#XZ'
EXPORT ord:0005='?LogParseError#ConfigCommon#awsiotsdk##KAXAEBW4ResponseCode#2#AEBV?$GenericDocument#U?$UTF8#D#rapidjson##V?$MemoryPoolAllocator#VCrtAllocator#rapidjson###2#VCrtAllocator#2##rapidjson##V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std###Z'
EXPORT ord:0006='?ReconnectCallback#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##V?$shared_ptr#VReconnectCallbackContextData#awsiotsdk###6#W443##Z'
EXPORT ord:0007='?ResubscribeCallback#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##V?$shared_ptr#VResubscribeCallbackContextData#awsiotsdk###6#W443##Z'
EXPORT ord:0008='?RunPublish#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#H#Z'
EXPORT ord:0009='?RunSample#PubSub#samples#awsiotsdk##QEAA?AW4ResponseCode#3#XZ'
EXPORT ord:0010='?Subscribe#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#XZ'
EXPORT ord:0011='?SubscribeCallback#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#V?$basic_string#DU?$char_traits#D#std##V?$allocator#D#2##std##0V?$shared_ptr#VSubscriptionHandlerContextData#mqtt#awsiotsdk###6##Z'
EXPORT ord:0012='?Unsubscribe#PubSub#samples#awsiotsdk##IEAA?AW4ResponseCode#3#XZ'
And also that it's building and running under a visual studio project where I can call the RunSample() function from the generated DLL file.
#include <iostream>
#include "PubSub.hpp"
int main()
{
awsiotsdk::samples::PubSub object1;
object1.RunSample();
}
My question is how can I port the example code above to run in a RAD studio C++ project? I tried using extern "C" __declspec(dllimport) in front of awsiotsdk::samples::PubSub object1 but it wasn't working.