的char *的printf的获取分割故障 [英] printf of char* gets Segmentation Fault

问题描述

我想从套接字和打印读取用printf（必须的），到标准输出;

I'm Trying to read from a socket and print to stdout using printf (a must);

不过，我得到一个分段错误每次我读了理智网站上的特定文件（HTML）的时间。

However I get a Segmentation Fault every time I read a specific file (an HTML) from the sane web site.

请，看看这个code和告诉我什么是错误的。

Please, take a look at this code and tell me what wrong.

int total_read = 0;
 char* read_buff = malloc(BUF_SIZE);
 char* response_data = NULL;
 if (read_buff == NULL){
  perror("malloc");
  exit(1);
 }
 while((nbytes = read(fd, read_buff, BUF_SIZE)) > 0){
  int former_total = total_read;
  total_read += nbytes;
  response_data = realloc(response_data, total_read);
  memmove(response_data + former_total, read_buff, nbytes); //start writing at the end of spot before the increase.
 }
 if (nbytes < 0){
  perror("read");
  exit(1);
 }

 printf(response_data);

感谢你。

推荐答案

RESPONSE_DATA 很可能不是NUL（'\\ 0'）终止，所以的printf 继续过去的字符串的结尾。或可能它包含了一个％指令，但的printf 无法找到进一步的参数。

response_data is probably not NUL ('\0') terminated, so printf continues past the end of the string. Or possibly it contains a % directive but printf can't find further arguments.

相反，告诉的printf 多远阅读，的不的国米preT任何％字符串中的指令。

Instead, tell printf how far to read, and not to interpret any % directives in the string.

printf("%.*s", total_read, response_data);

请注意，如果 RESPONSE_DATA 包含一个内嵌的NULL，的printf 将停在那里，即使 total_read 是更长的时间。

Note that if response_data contains an embedded NUL, printf will stop there even if total_read is longer.

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