Question for Tutorial code

[boostorg]

Question for Tutorial code

[klemens-morgenstern]

The warning shouldn't be there (anymore). The pipe-sink is closed on the parent side, so there won't be any deadlock.

Nm also writes out an empty line at the end, so it would be fine otherwise.

[tanxn5]

Thanks. maybe i misunderstood something, this routine:

1. c.runing() = true
2. (nm exited...)
3. std::getline(is, line) ---> is it safe?

because there is a tutorial warning

Warning
--
The pipe will cause a deadlock if you try to read after nm exited

[klemens-morgenstern]

Then the loop condition isn't fulfilled and child.wait reaps the zombie process from the table.

[tanxn5]

Thanks.

[vt-alt]

@klemens-morgenstern But aren't FAQ is incorrect too?

[section:closep Why does the pipe not close?]

Now for another example, which might look correct, let's consider you want
to use `ls` to read the current directory.

ipstream is;
child c("ls", std_out > is);

std::string file;
while (is >> file)
    cout << "File: " << file << endl;


This will also deadlock, because the pipe does not close when the subprocess exits.
So the `ipstream` will still look for data even though the process has ended.

[note It is not possible to use automatic pipe-closing in this library, because
a pipe might be a file-handle (as for async pipes on windows).]

The example code does not deadlock anymore too.