CODEWITHSUNDEEP
c++functionmacrosc++17
Raildex
Raildex

Reputation: 4817

Replace logging macro with function

I have the following macro definition:

#if DEBUG
#include <iostream>
#include <ostream>
#define LOG(x) std::cout << x << std::endl;
#else 
#define LOG(x) // LOG(x) is replaced with nothing in non-debug
#endif

How would an equivalent function look like that allows this?:

LOG("This is a Test message" << " with " << testVariable << " a variable");

my current implementation looks like this:

template <typename T>
inline void logD(const T& x) {
    if constexpr (Debug) {
        std::cout << x << std::endl;
    }
};

but I get the following error:

error C2296: '<<': illegal, left operand has type 'const char [25]'

replacing << with + for concatenating doesnt help either

 error C2110: '+': cannot add two pointers

Upvotes: 0

Views: 427

Answers (2)

Raildex
Raildex

Reputation: 4817

With the help of Mooing_Duck i made the function a vararg template and simply use the parameter pack.

template <typename ...T>
inline void logD(const T&... x) {
    if constexpr (DebugBuild) {
        (std::cout << ... << x) << std::endl;
    }
};

you call the function with separated commas for the content.

logD("This is a ","test with a ",variable," variable");

Upvotes: 1

b00rt00s
b00rt00s

Reputation: 112

The first part of function argument must be a well-defined type that can be used with standard streams, e.g:

std::string testVariable = "test";
LOG(std::string("This is a Test message") + " with " + testVariable + " a variable");

Upvotes: 0

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