constant multidimensional array in a function argument

[Szabolcs Borsanyi]

The following code compiles with a warning message:
passing arg 1 of `use_vector' from incompatible pointer type

How can one correctly pass a multidimensional array (by reference)
expressing that 'use_vector'
is not meant to modify any of the elements.

Thanks
Szabolcs

------------------------------------------------------------
enum { E=3 };
typedef double vector[4];

void use_vector(const vector x[E])
{
}

int main()
{
vector v[E]={0};
use_vector(v);
}

 

[Ben Bacarisse]

The following code compiles with a warning message:
passing arg 1 of `use_vector' from incompatible pointer type

Yes, you have hit a small hole in the way C handles qualified types.

How can one correctly pass a multidimensional array (by reference)
expressing that 'use_vector'
is not meant to modify any of the elements.

Pretty much all you can do is use a cast:

use_vector((const vector *)v);

(or drop the const from the parameter).

enum { E=3 };
typedef double vector[4];

void use_vector(const vector x[E])
{
}

int main()
{
vector v[E]={0};
use_vector(v);
}