curl 使用的疑惑 回调接口 数据为空

[hzy694358]

size_t write_data_callback(void *ptr, size_t size, size_t nmemb, void *buf)
{
    printf("ptr:%s,size:%d,nmemb:%d\n",ptr,size,nmemb);
    strncat(buf, ptr, size*nmemb);
    return size*nmemb;
}

结果：
59 ptr:遅^MT/,size:1,nmemb:2441
60 ptr:,size:1,nmemb:1448
61 ptr:,size:1,nmemb:2896
62 ptr:,size:1,nmemb:2896
63 ptr:,size:1,nmemb:1448
64 ptr:,size:1,nmemb:2896
65 ptr:,size:1,nmemb:2896
66 ptr:,size:1,nmemb:1448
67 ptr:,size:1,nmemb:2896
68 ptr:,size:1,nmemb:2896
69 ptr:,size:1,nmemb:1448
70 ptr:,size:1,nmemb:2896
71 ptr:,size:1,nmemb:2896
72 ptr:,size:1,nmemb:1448
73 ptr:,size:1,nmemb:2896
……
---------------------------------------
ptr 的数据都是空，同样的方式获取其他网页数据都是可以的，不知为何 就单单这一个不行；
url 地址：http://www.nic.top/upload/top/dellista.txt

求解释

[赵4老师]

仅供参考：

void HexDump(char *buf,int len,int addr) {
    int i,j,k;
    char binstr[80];

    for (i=0;i<len;i++) {
        if (0==(i%16)) {
            sprintf(binstr,"%08x -",i+addr);
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
        } else if (15==(i%16)) {
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
            sprintf(binstr,"%s  ",binstr);
            for (j=i-15;j<=i;j++) {
                sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');
            }
            printf("%s\n",binstr);
        } else {
            sprintf(binstr,"%s %02x",binstr,(unsigned char)buf[i]);
        }
    }
    if (0!=(i%16)) {
        k=16-(i%16);
        for (j=0;j<k;j++) {
            sprintf(binstr,"%s   ",binstr);
        }
        sprintf(binstr,"%s  ",binstr);
        k=16-k;
        for (j=i-k;j<i;j++) {
            sprintf(binstr,"%s%c",binstr,('!'<buf[j]&&buf[j]<='~')?buf[j]:'.');
        }
        printf("%s\n",binstr);
    }
}