程序代码：

char* gets_safe()
{
    const int LENGTH = 1;
    size_t len = 0;
    char* ret = NULL;
    char buffer[LENGTH + 1] = {0};

    while( LENGTH != 0 ){
        size_t iLen = 0;
        if( fgets(buffer, LENGTH + 1, stdin) == NULL ){
            buffer[0] = 0;
            break;
        }
        iLen = strlen(buffer);
        if(iLen != 0){
            if( ret == NULL )
                ret = (char*)malloc(iLen + 1);
            else{
                char* tmp = (char*)malloc(len + iLen + 1);
                strncpy(tmp, ret, len);
                free(ret);
                ret = tmp;
            }
            strncpy(ret + len, buffer, iLen);
            len += iLen;
            ret[len] = 0;
        }
        if(buffer[iLen - 1] == 0x0A){
            ret[len - 1] = 0;
            break;
        }
    }
    fflush(stdin); // 在这个函数将要退出前，对 stdin 里应该给予清空处理
    return ret;
}