I want to make a struct that includes a matrix of string

I want to makes a struct that include a matrix of string.

Like |0|1|2|..|10
each one of this position should have strings like this: hello, world, 1234, …

I want to add string unless I get the limit (= SO_BLOCK_SIZE), so I create a function to know how many string I already added. I got some errors like these:

error: expected declaration specifiers or ‘…’ before numeric constant
#define SO_REGISTRY_SIZE 10

note: in expansion of macro ‘SO_REGISTRY_SIZE’
char (*matrice)(SO_REGISTRY_SIZE);

warning: no semicolon at end of struct or union

error: ‘libroMastro’ {aka ‘struct libroMastro’} has no member named ‘matrice’
if((libro->matrice[i][j]) == NULL)

Here is my code:

    #include <stdio.h>
    #include <stdlib.h>
    
    #define BUF_SIZE 64
    #define SO_REGISTRY_SIZE 10
    #define SO_BLOCK_SIZE 5
    
    typedef struct libroMastro{
        char (*matrice)(SO_REGISTRY_SIZE);
    }libroMastro;
    
    int whatIndex(libroMastro *libro){
        int i = 0;
        int j = 0;
        for(i; i < SO_REGISTRY_SIZE; i++){
            for(j; j < SO_BLOCK_SIZE; j++){
                if((libro->matrice[i][j]) == NULL)
                    return j;
            }
        }
    
        return j;
    }
    
    int main(){
        libroMastro *libro;
        whatIndex(libro);
    }

>Solution :

Your code is invalid in may places.

I would implement it this way:

typedef struct libroMastro
{
    size_t nmessages;
    char *matrice[];
}libroMastro;

libroMastro *addString(libroMastro *lm, const char *str)
{
    if(str)
    {
        size_t newsize = lm ? lm -> nmessages + 1 : 1;
        lm = realloc(lm, sizeof(*lm) + newsize * sizeof(lm -> matrice[0]));
        if(lm)
        {
            if((lm -> matrice[newsize - 1] = strdup(str)))
            {
                lm -> nmessages = newsize;
            }
            else
            {
                lm -> nmessages = newsize - 1;
            }
        }
    }
    return lm;
}

size_t how_many(libroMastro *lm)
{
    if(lm) return lm -> nmessages;
}


int main(){
    libroMastro *libro = NULL;


    libro = addString(libro, "Hello");
    libro = addString(libro, "World");
    libro = addString(libro, "Next");

    printf("Libro contains %zu strings\n", libro -> nmessages);
}