管道损坏时的发送行为
在编写一个简单的服务器客户端应用程序时，我想到了这个问题。当有人尝试写入损坏的管道时，会生成 SIGPIPE。假设我在代码中处理信号。
现在 write 调用返回什么错误 - EPIPE 或 EINTR （因为它被信号中断）。我尝试了一个示例程序，似乎总是得到 EPIPE。这是有保证的行为还是可能是两个错误值中的任何一个？
While writing a simple server-client application, this question came in my mind. When someone tries to write to a broken pipe, a SIGPIPE would be generated. Let's say I handle the signal in my code.
Now what error does the write call returns - EPIPE or EINTR ( as it was interrupted by a signal). I tried with a sample program and I seem to be getting EPIPE always. Is this a guaranteed behavior or it could be any of the two error values?
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（3）
POSIX 规定应返回 EPIPE 并发送 SIGPIPE：
您可以在此处查看 POSIX 标准
POSIX says that EPIPE should be returned and SIGPIPE sent:
You can have a look at the POSIX standard here
write(2)调用返回- 1错误，所以我猜您是在询问errno 的值(3)。如果您处理、阻止或忽略信号，您将获得
EPIPE。否则进程默认终止，参见signal(7)。The
write(2)call returns-1on error, so I guess you are asking about the value oferrno(3).You'll get
EPIPEif you handle, block, or ignore the signal. Otherwise the process is terminated by default, seesignal(7).一般来说，“被信号中断”（EINTR）是指完全荒谬的 Unix System V 信号处理，如果您的进程在系统调用期间接收（并处理）信号，任何系统调用都可能失败。这需要用
do ... while (ret==-1 && errno==EINTR); 或类似的方法包装每个系统调用。虽然 POSIX 仍然允许这种行为或良好的（“BSD”）行为，但像 GNU/Linux 这样的健全系统默认情况下具有 BSD 行为。您始终可以通过使用正确的参数调用 sigaction 来获取 BSD 行为，甚至可以创建一个包装函数来为您执行此操作。因此，EINTR 与写入错误引起的 SIGPIPE 无关。
In general, "interrupted by a signal" (EINTR) refers to the utterly ridiculous Unix System V signal handling, whereby ANY system call could fail if your process received (and handled) a signal during the system call. This required wrapping every system call with
do ... while (ret==-1 && errno==EINTR);or similar. While POSIX still allows either this or the good ("BSD") behavior, sane systems like GNU/Linux have the BSD behavior by default. You can always obtain the BSD behavior by callingsigactionwith the right arguments, or even make a wrapper function to do so for you.As such, EINTR is unrelated to the SIGPIPE caused by write errors.