关闭boost :: process子的stdin [英] Close the stdin of boost::process child

问题描述

我正在尝试使用Boost-1.64.0调用一个带有标准输入法的字符串的进程. 当前代码是:

I'm trying to call a process with a string to its stdin, with Boost-1.64.0. The current code is :

  bp::opstream inStream ;
  bp::ipstream outStream;
  bp::ipstream errStream;

  bp::child child(
    command, // the command line
    bp::shell,
    bp::std_out > outStream,
    bp::std_err > errStream,
    bp::std_in  < inStream);


  // read the outStream/errStream in threads

  child.wait();

问题在于子可执行文件正在等待其标准输入EOF.这里child.wait()无限期地挂起……

The problem is that the child executable is waiting for its stdin EOF. Here child.wait() is hanging indefinitely…

我尝试使用asio :: buffer，std_in.close()，……但是没有运气. 我发现的唯一破解方法是delete()inStream…这并不是很可靠.

I tried to used asio::buffer, std_in.close(),… But no luck. The only hack I found was to delete() the inStream… And that's not really reliable.

我应该如何通知"子进程并使用新的boost :: process库关闭其stdin?

How am I supposed to "notify" the child process and close its stdin with the new boost::process library ?

谢谢！

推荐答案

我尝试使用asio :: buffer，std_in.close()

这有效.当然，只有将其传递给启动函数(bp :: child构造函数，bp :: system等)时，它才起作用.

This works. Of course it only works if you pass it to a launch function (bp::child constructor, bp::system, etc).

如果需要传递数据，然后将其关闭，只需关闭关联的filedescriptor.我做这样的事情:

If you need to pass data, and then close it, simply close the associated filedescriptor. I do something like this:

boost::asio::async_write(input, bp::buffer(_stdin_data), [&input](auto ec, auto bytes_written){
    if (ec) {
        logger.log(LOG_WARNING) << "Standard input rejected: " << ec.message() << " after " << bytes_written << " bytes written";
    }
    may_fail([&] { input.close(); });
});

input的位置

bp::async_pipe input(ios);

还要检查发送输出的过程实际上没有卡死！如果您无法使用输出，它将正在缓冲并等待缓冲区是否已满.

Also, check that the process is not actually stuck sending the output! If you fail to consume the output it would be buffering and waiting if the buffer is full.

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