pass dynamic array of pointers to C function - c

Question

I want to store each line of the file in an 2D array, and anthor array pointing each line (so I can identify each line), I need to pass this pointers array to a function so I can manipulate my lines, I d'ont know how to do that
I have this code to read and store in the arrays
char ligne[MAX];
//open end test the file
FILE* fichier = fopen("csp.txt","r");
if(fichier == NULL){
printf("can't open the file \n");
return EXIT_FAILURE;
}
//the first line in the file contain number of other lines
fgets(ligne, sizeof(ligne), fichier);
int nbrTaille = strtol(ligne, NULL, 10);
//array of pointers
char (*tab)[nbrTaille] = malloc(nbrTaille * sizeof(ligne));
int i = 0;
//tab array point each line
while(fgets(ligne, sizeof(ligne), fichier)){
if(ligne == NULL) EXIT_FAILURE;
strncpy(tab[i], ligne, strlen(ligne));
printf("line%d : %s\n", i, tab[i]);
i++;
}
//call the funnction by passing array of pointers and the number of lines
allDiff(tab, nbrTaille);
the file I'm reading is
2
1 2
2 3
to receive the array by the function I tried this but it doesn't work
void allDiff(char** T, int taille)

Answer 1

I am always confused with the parenthesies and asterisks. The easier way is to declare a double pointer:
char ** tab;
//you need to take care of errors. I am not doing it for simplicity
//tab = {pointer1, pointer2, pointer3, ...., pointerN} total memory needed N * sizeof(pointer)
tab = malloc(lines* sizeof(tab)); //how many pointers you want
for(i = 0; i < lines; i++){
tab[i] = malloc(MAX); //each string
}
In the end free the memory:
for(i = 0; i < lines; i++){
free(tab[i]);
}
free(tab);
EDIT complete code
char ligne[MAX];
//open end test the file
FILE* fichier = fopen("csp.txt","r");
if(fichier == NULL){
printf("can't open the file \n");
return EXIT_FAILURE;
}
//the first line in the file contain number of other lines
fgets(ligne, sizeof(ligne), fichier);
int nbrTaille = strtol(ligne, NULL, 10);
//array of pointers
//char (*tab)[nbrTaille] = malloc(nbrTaille * sizeof(ligne));
int i = 0;
char **tab;
tab = malloc(nbrTaille * sizeof(tab)); //how many pointers you want
for(i = 0; i < nbrTaille; i++){
//sizeof(ligne) is equal to MAX
tab[i] = malloc(MAX); //each string
}
i = 0;
//tab array point each line
while(fgets(ligne, sizeof(ligne), fichier)){
if(ligne == NULL) EXIT_FAILURE;
strncpy(tab[i], ligne, strlen(ligne));
printf("line%d : %s\n", i, tab[i]);
i++;
}
//call the funnction by passing array of pointers and the number of lines
allDiff(tab, nbrTaille);

Answer 2

void function(char tab[][MAXLEN], ...);
This will do.

Answer 3

For the sake of readbility and sanity, typedef C function pointers before creating arrays or double pointers to them.
/* typedef the function pointer. An ftabptr points to a void function that
takes a char * */
typedef void (*ftabptr)(char *p);
/* create an uninitalised list of twenty of them */
int N = 20;
ftabptr *pointerlist = malloc(N * sizeof(ftabptr));
However I don't think you really want to do this. You can write a
functioning program that does weird things with tables of function
pointers, but normally you use a language other than C if you
want to play that game (Lisp-like languages, etc). The high level
language then often emits C as an intermediate step.