是否有可靠地使用write（）函数一个更清洁的方式？ [英] Is there a cleaner way to use the write() function reliably?

问题描述

我读人页，我的理解是，如果的write（）将失败，并将在错误号到 EAGAIN 或 EINTR ，我可以执行的write（）了，所以我想出了以下code：

I read the man pages, and my understanding is that if write() fails and sets the errno to EAGAIN or EINTR, I may perform the write() again, so I came up with the following code:

  ret = 0;
  while(ret != count) {
    write_count = write(connFD, (char *)buf + ret,  count);
    while (write_count < 0) {
      switch(errno) {
        case EINTR:
        case EAGAIN:
          write_count = write(connFD, (char *)buf + ret,  count -ret);
          break;
        default:
          printf("\n The value of ret is : %d\n", ret);
          printf("\n The error number is : %d\n", errno);      
          ASSERT(0);
      }
    }
    ret += write_count;
  }

我执行阅读（）和的write（）上的插座和处理阅读（）类似如上。我使用Linux，以 GCC 编译器。

I am performing read() and write() on sockets and handling the read() similarly as above. I am using Linux, with gcc compiler.

推荐答案

您有一个有点不重复自己的问题存在 - 没有必要为两个单独的呼叫到写，也有两个嵌套循环。

You have a bit of a "don't repeat yourself" problem there - there's no need for two separate calls to write, nor for two nested loops.

我的正常循环就会是这个样子：

My normal loop would look something like this:

for (int n = 0; n < count; ) {
    int ret = write(fd, (char *)buf + n, count - n);
    if (ret < 0) {
         if (errno == EINTR || errno == EAGAIN) continue; // try again
         perror("write");
         break;
    } else {
        n += ret;
    }
}

// if (n < count) here some error occurred

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