C-结构错误的动态数组

Question

I'm trying to implement a multithreaded C program and I'm stuck. I have a struct which holds a char array and a pointer to another struct (I'm trying to use that pointer as an array of buffer_item s:

typedef struct{

    char** buffer;
} buffer_item;

typedef struct{

    buffer_item* buffers;
    char file_name[255];

}buffer_holder;

When I try to create buffer_item s and put them into buffer_holder 's buffers array, gcc gives me the following error:

for(i = 0; i < n_value; i++){

        buffer_holder *holder = (buffer_holder*) malloc(sizeof(buffer_holder));
        int l;

        for(l = 0; l < r_value; l++){

            buffer_item *new_item  = (buffer_item *)malloc(sizeof(buffer_item));
            new_item->buffer = malloc(buffer_size * sizeof(char*));
            int j;
            for (j = 0; j < buffer_size; j++)
                new_item->buffer[j] = malloc((MAX_WORD+1) * sizeof(char));

            holder -> buffers[l] = new_item;
        }
        strcpy(holder -> file_name, argv[i+3]);

        if(pthread_create(&mapper_threads[i], NULL, mapper, (void*) holder)) {

            fprintf(stderr, "Error creating thread\n");
            return 1;
        }
    }

wcountb2.c:187:28: error: incompatible types when assigning to type 'buffer_item' from type 'struct buffer_item *' holder -> buffers[l] = new_item;

I have been trying to solve it but could not find anything. Any help will be appreciated. Thank you all.

Answer 1

holder->buffers is a pointer to struct buffer_item , but in the assignment holder->buffers[l] = new_item you treat it like an array of pointers.

to fix it just change holder->buffers[l] = new_item; into holder->buffers = new_item;