Question

I have a large codebase that recently moved from Microsoft’s compiler to the Intel C++ Compiler. Our team’s goal is compilation without warnings in the mainline. Since the switch, one instance of warning 167 has confounded me. If I compile the following code:

int foo(const int pp_stuff[2][2])
{
   return 0;
}

int foo2(const int pp_stuff[][2])
{
    return 0;
}


int main(void)
{
    int stuff[2][2] = {{1,2},{3,4}};

    foo(stuff);
    foo2(stuff);

    return 0;
}

The ICC will give me warnings:

1>main.c(17): warning #167: argument of type "int (*)[2]" is incompatible with parameter of type "const int (*)[2]"
1>        foo(stuff);
1>            ^
1>  
1>main.c(18): warning #167: argument of type "int (*)[2]" is incompatible with parameter of type "const int (*)[2]"
1>        foo2(stuff);

Why should this be a warning? It is common practice to pass a non-const variable as a const parameter, and the types & dimensions are identical.

To those who have marked this a duplicate question, I urge you to reconsider. If someone else encounters this warning, they would have to know that in C arguments are converted as if by assignment in prototyped functions, and then search for a question that is strictly about assignment. Even though the answer ends up being the same clause from C90/C99, the question is, I think, pretty different.

Answer 1

Cast your variable as const when you pass it to the function that requires const.

foo( (const int (*)[2]) stuff );

Why can’t I pass a char ** to a function which expects a const char **?

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