arrays - 灵活数组成员使用无效错误

Question

typedef struct {
        void *end;
        void *start;
        int size;
        int arrs [];
        } st;


void *doStuff(void *starter, void *ender) {
    st *s = (st *) malloc(sizeof(st));
    s->end = ender;
    s->start = starter;
    int sayz = 1;
    s->size = (int) (ender - starter);
    int a [s->size];
    memset(a, 0, sizeof a);
    s->arrs = a; // This line gives error
    return s;
    }

行“st->arrs = a;”给我“灵活数组成员的无效使用”错误。有谁知道如何在结构中保存数组？语言是C

Answer 1

这就是您想要的，假设 starter 和 ender 指向 char 对象。我还清理了您的缩进和格式。

typedef struct {
    void *end;
    void *start;
    ptrdiff_t size;  // Note that a diff of pointers should be a ptrdiff_t
    int arrs[];
} st;

st *doStuff(void *starter, void *ender) {
    ptrdiff_t size = (char*)ender - (char*)starter; // Calculate size first so it's available to use in malloc
    st *s = malloc(size + sizeof st);
    s->end   = ender;
    s->start = starter;
    s->size  = size;
    memset(s->arrs, 0, size * sizeof s->arrs[0]); // since array is allocated, no need to create a redundant array
    return s;
}