Assigning memory to double pointer?

Question

I am having trouble understanding how to assign memory to a double pointer. I want to read an array of strings and store it.

    char **ptr;
    fp = fopen(\         


        

Answer 1

Adding to Pent's answer, as he correctly pointed out, you will not be able to use this double pointer once the function returns, because it will point to a memory location on the function's activation record on stack which is now obsolete (once the function has returned). If you want to use this double pointer after the function has returned, you may do this:

char * realptr = (char *) malloc(1234);
char ** ptr = (char **) malloc(sizeof(char *));
*ptr = realptr;
return ptr;

The return type of the function must obviously be char ** for this.