reallocできない

失敗例.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

//Utils(ファイル分割すべきだけど設定がめんどくさいので)

typedef struct
{
    int len;
    char str[];
} istring;

istring* getIstring(char chars[], int length){
    istring* ret = malloc(sizeof(istring) + sizeof(char)*length);

    ret->len = length;
    strcpy(ret->str, chars);

    return ret;
}

//プロトタイプ宣言

char* lzw_c(char raw_c[], int length);

//メイン

int main(){
    char raw[] = "010101010";

    char* comped = lzw_c(raw, sizeof(raw) / sizeof(char));
    printf("%s\n", comped);

    return 0;
}

//ユーザー定義関数

char* lzw_c(char raw_c[], int length){
    istring* raw = getIstring(raw_c, length);

    printf("arg|raw_c: %s\n", raw->str);
    printf("arg|length: %d\n", raw->len);

    istring *dic;//辞書
    int dic_pages = 0;

    istring w = *getIstring("", 0);
    istring k = *getIstring("", 0);

    int exist_flag = 0;
    //辞書の初期化処理
    for(int i = 0; i < length; i++){
        if(raw_c[i] == '\0') break;
        //printf("arg|raw_c[%d]: %c\n", i, raw_c[i]);
        //辞書にすでに登録されているか判定
        exist_flag = 0;
        for(int j = 0; j < dic_pages; j++){
            if(dic[j].str[0] == raw_c[i]){
                exist_flag = 1;
                break;
            }
        }
        //辞書に登録されていなかったら,登録
        if(exist_flag == 0){
            printf("dic|register <%c> to page %d\n", raw_c[i], dic_pages);
            printf("dic|old_size: %d\n", sizeof(*dic));
            printf("dic|pointer: %p\n", dic);
            char newword[] = {raw_c[i]};
            istring* newpage = getIstring(newword, 1);
            istring* temp = realloc(dic, sizeof(*dic) + sizeof(*newpage));
            printf("dic|new_size: %d\n", sizeof(*dic) + sizeof(*newpage));
            if(temp == NULL){
                printf("dic|ERROR OCCURED\n");
                exit(1);
            }else{
                dic = temp;
                dic[dic_pages] = *newpage;
                dic_pages++;
            }
        }
    }

    return "Not implemented";
}

出力
arg|raw_c: 010101010
arg|length: 10
dic|register <0> to page 0
dic|old_size: 4
dic|pointer: 0061FFCC
dic|new_size: 8
dic|ERROR OCCURED

https://twitter.com/pepepper_cpp/status/1302257807094235136
https://t.co/Z55RCOR6mf?amp=1
フレキシブル配列メンバを含む構造体の配列は使ってはいけない
END