Lookup #define value dll - c++

Question

This may turn out to be a really easy question, but made very difficult by me not having used C++ in serious anger for a long time - my skills are rustier than an 80's Fiat!
I have a number of header files that define register addresses as #defines that have been provided to me.
I want to create a .dll that allows me to lookup these values via their name and returns their value as an unsigned long from another dev environment i.e.
#define A_REGISTER_ADDRESS 0x40
unsigned long myLookupFunction( string lookup )
{
// return value of #define specified by lookup as unsigned long
}
Thanks in advance for any help.
Dave

Answer 1

You could use a technique like this. This uses a macro generator to produce a std::map from the string name to the value and an enum with the same names and values.
#include <map>
#include <iostream>
#include <string>
#define ADDRESS(apply) \
apply(PORT1,0x40UL) \
apply(PORT2,0x42UL) \
apply(PORT3,0x43UL)
#define CREATE_MAP(name,value) \
{#name,value},
std::map<std::string, unsigned long> myMap = {ADDRESS(CREATE_MAP)};
#define CREATE_ENUM(name, value) \
name = value,
enum RegisterAddresses
{
ADDRESS(CREATE_ENUM)
};
unsigned long myLookupFunction(std::string lookup)
{
return myMap[lookup];
}
int main()
{
std::cout << "port PORT1 value " << std::hex << myLookupFunction("PORT1") << "\n";
std::cout << "port PORT2 value " << std::hex << myLookupFunction("PORT2") << "\n";
std::cout << "port PORT3 value " << std::hex << myLookupFunction("PORT3") << "\n";
std::cout << "port PORT1 enum value " << std::hex << PORT1 << "\n";
}