CODEWITHSUNDEEP
c++pointersconstexpr
Serket
Serket

Reputation: 4465

error: cannot initialize a variable of type 'int *const' with an rvalue of type 'const int *

Why am I getting this error: error: cannot initialize a variable of type 'int *const' with an rvalue of type 'const int * when compiling the following code? Code:

constexpr int ch1 = 5;
constexpr int* pch1 = &ch1;
constexpr int ch2 = 5;
constexpr int* pch2 = &ch2;

cout << *pch1+*pch2;

Let me make this clear. The point of this whole ordeal is to initialise these variables at compile time. If there's a better way to do this, please let me know.

Upvotes: 1

Views: 2939

Answers (1)

catnip
catnip

Reputation: 25388

The fact that you have declared pch1 and pch2 as constexpr does not of itself make them const int *, so you would need:

constexpr int ch1 = 5;
constexpr const int* pch1 = &ch1;
constexpr int ch2 = 5;
constexpr const int* pch2 = &ch2;

However, then you get:

error: '& ch1' is not a constant expression
error: '& ch2' is not a constant expression

So you're still not winning.

Live demo

Edit: As chris points out, you can fix the latter problem by declaring ch1 and ch2 as static. Their addresses then become constexpr:

constexpr static int ch1 = 5;
constexpr const int* pch1 = &ch1;
constexpr static int ch2 = 5;
constexpr const int* pch2 = &ch2;

Live demo

Upvotes: 1

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