试图释放这个二维数组

Question

When I run the app it seg faults when it gets to the destroy function and I don't know why. Any thoughts would be great maybe its from the allocating function but everything worked fine until I made the destroy function.

int main(void)
{
    char** strings;
    allocate(&strings, 48);
    //....does stuff with data
    destroy(&strings, 48);
}

void allocate(char ***strings, int size)
{
    *strings = (char**)malloc(size * sizeof(char*));
    if(strings == NULL)
    {
            printf("Could not allocate memory\n");
    }

    int i;
    for(i=0;i<size;i++)
    {
            (*strings)[i] = (char*)malloc(MAX_STRING_LEN * sizeof(char));
            if(strings == NULL)
            {
                    printf("Could not allocate memory\n");
            }
    }
}



void destroy(char ***strings, int size)
{
    int j;
    for(j=0;j<size;j++)
    {
            free(strings[j]);
    }
    free(strings);
}

Answer 1

You forgot to dereference the strings pointer in destroy function:

void destroy(char ***strings, int size)
{
    int j;
    for(j=0;j<size;j++)
    {
            free( (*strings)[j] );
    }
    free(*strings);
}