This isn't specifically a D question, but seeing as it's for a D library I figure it can go here :)

On Windows, I want to be able to spawn a console and then interact with its stdin/out asynchronously, similar to how forkpty [1] works on linux.

I'm improving my dexpect library [2] to work with windows machines and this bit has me stumped. There doesnt seem to be much info about it that I can find (though my google-fu mightn't be good enough!!)

I'm sure theres someone here who knows something?

Thanks!

[1] http://linux.die.net/man/3/forkpty
[2] https://github.com/grogancolin/dexpect

On 10/05/2015 12:13 a.m., wobbles wrote:
> This isn't specifically a D question, but seeing as it's for a D library
> I figure it can go here :)
>
> On Windows, I want to be able to spawn a console and then interact with
> its stdin/out asynchronously, similar to how forkpty [1] works on linux.
>
> I'm improving my dexpect library [2] to work with windows machines and
> this bit has me stumped. There doesnt seem to be much info about it that
> I can find (though my google-fu mightn't be good enough!!)
>
> I'm sure theres someone here who knows something?
>
> Thanks!
>
> [1] http://linux.die.net/man/3/forkpty
> [2] https://github.com/grogancolin/dexpect

Did you try creating a new process which is cmd?
Because std.process should be able to handle the IO part.

On Saturday, 9 May 2015 at 12:16:52 UTC, Rikki Cattermole wrote:
> On 10/05/2015 12:13 a.m., wobbles wrote:
>> This isn't specifically a D question, but seeing as it's for a D library
>> I figure it can go here :)
>>
>> On Windows, I want to be able to spawn a console and then interact with
>> its stdin/out asynchronously, similar to how forkpty [1] works on linux.
>>
>> I'm improving my dexpect library [2] to work with windows machines and
>> this bit has me stumped. There doesnt seem to be much info about it that
>> I can find (though my google-fu mightn't be good enough!!)
>>
>> I'm sure theres someone here who knows something?
>>
>> Thanks!
>>
>> [1] http://linux.die.net/man/3/forkpty
>> [2] https://github.com/grogancolin/dexpect
>
> Did you try creating a new process which is cmd?
> Because std.process should be able to handle the IO part.

I have, but they all block i/o and so I cant continually read from its output :/

On Saturday, 9 May 2015 at 12:25:32 UTC, wobbles wrote:
> On Saturday, 9 May 2015 at 12:16:52 UTC, Rikki Cattermole wrote:
>> On 10/05/2015 12:13 a.m., wobbles wrote:
>>> This isn't specifically a D question, but seeing as it's for a D library
>>> I figure it can go here :)
>>>
>>> On Windows, I want to be able to spawn a console and then interact with
>>> its stdin/out asynchronously, similar to how forkpty [1] works on linux.
>>>
>>> I'm improving my dexpect library [2] to work with windows machines and
>>> this bit has me stumped. There doesnt seem to be much info about it that
>>> I can find (though my google-fu mightn't be good enough!!)
>>>
>>> I'm sure theres someone here who knows something?
>>>
>>> Thanks!
>>>
>>> [1] http://linux.die.net/man/3/forkpty
>>> [2] https://github.com/grogancolin/dexpect
>>
>> Did you try creating a new process which is cmd?
>> Because std.process should be able to handle the IO part.
>
> I have, but they all block i/o and so I cant continually read from its output :/

What I mean is, if the cmd.exe hasnt flushed it's output, my cmdPid.stdout.readln (or whatever) will block until it does. I dont really want this.

I guess I need to make another thread to do this so I wont block the main thread?

On Saturday, 9 May 2015 at 12:26:58 UTC, wobbles wrote:
> What I mean is, if the cmd.exe hasnt flushed it's output, my cmdPid.stdout.readln (or whatever) will block until it does. I dont really want this.

Are you sure cmd is the culprit? It should have sensible buffering. Also do you want just a console window or also a command interpreter attached to it?

On Saturday, 9 May 2015 at 12:48:16 UTC, Kagamin wrote:
> On Saturday, 9 May 2015 at 12:26:58 UTC, wobbles wrote:
>> What I mean is, if the cmd.exe hasnt flushed it's output, my cmdPid.stdout.readln (or whatever) will block until it does. I dont really want this.
>
> Are you sure cmd is the culprit? It should have sensible buffering. Also do you want just a console window or also a command interpreter attached to it?

My windows knowledge isnt marvelous, but I believe I'll need the interpreter attached.

Just as an example of running cmd through std.process, running this on my system:
	auto pipes = pipeShell("cmd.exe");
	write(pipes.stdout.readln);
	write(pipes.stdout.readln);
	write(pipes.stdout.readln);
        return;
will print
`
Microsoft Windows [Version 6.3.9600]
(c) 2013 Microsoft Corporation. All rights reserved.

`
and then exits.

However, adding another "write" line before the return; will cause the program to hang there, waiting for the cmd.exe process to flush it's next line.

On Linux, I'm able to edit a file descriptor after I've created it to tell it to read/write asynchronously, I cant seem to find anything similar on windows however.

On Saturday, 9 May 2015 at 13:00:01 UTC, wobbles wrote:
> On Saturday, 9 May 2015 at 12:48:16 UTC, Kagamin wrote:
>> On Saturday, 9 May 2015 at 12:26:58 UTC, wobbles wrote:
>>> What I mean is, if the cmd.exe hasnt flushed it's output, my cmdPid.stdout.readln (or whatever) will block until it does. I dont really want this.
>>
>> Are you sure cmd is the culprit? It should have sensible buffering. Also do you want just a console window or also a command interpreter attached to it?
>
> My windows knowledge isnt marvelous, but I believe I'll need the interpreter attached.
>
> Just as an example of running cmd through std.process, running this on my system:
> 	auto pipes = pipeShell("cmd.exe");
> 	write(pipes.stdout.readln);
> 	write(pipes.stdout.readln);
> 	write(pipes.stdout.readln);
>         return;
> will print
> `
> Microsoft Windows [Version 6.3.9600]
> (c) 2013 Microsoft Corporation. All rights reserved.
>
> `
> and then exits.
>
> However, adding another "write" line before the return; will cause the program to hang there, waiting for the cmd.exe process to flush it's next line.
>
> On Linux, I'm able to edit a file descriptor after I've created it to tell it to read/write asynchronously, I cant seem to find anything similar on windows however.

Spoke too soon. Looks like this is what I need:
http://www.codeproject.com/Articles/534/An-Introduction-to-Processes-Asynchronous-Process

On Saturday, 9 May 2015 at 13:01:27 UTC, wobbles wrote:
> On Saturday, 9 May 2015 at 13:00:01 UTC, wobbles wrote:
>> On Saturday, 9 May 2015 at 12:48:16 UTC, Kagamin wrote:
>>> On Saturday, 9 May 2015 at 12:26:58 UTC, wobbles wrote:
>>>> What I mean is, if the cmd.exe hasnt flushed it's output, my cmdPid.stdout.readln (or whatever) will block until it does. I dont really want this.
>>>
>>> Are you sure cmd is the culprit? It should have sensible buffering. Also do you want just a console window or also a command interpreter attached to it?
>>
>> My windows knowledge isnt marvelous, but I believe I'll need the interpreter attached.
>>
>> Just as an example of running cmd through std.process, running this on my system:
>> 	auto pipes = pipeShell("cmd.exe");
>> 	write(pipes.stdout.readln);
>> 	write(pipes.stdout.readln);
>> 	write(pipes.stdout.readln);
>>        return;
>> will print
>> `
>> Microsoft Windows [Version 6.3.9600]
>> (c) 2013 Microsoft Corporation. All rights reserved.
>>
>> `
>> and then exits.
>>
>> However, adding another "write" line before the return; will cause the program to hang there, waiting for the cmd.exe process to flush it's next line.
>>
>> On Linux, I'm able to edit a file descriptor after I've created it to tell it to read/write asynchronously, I cant seem to find anything similar on windows however.
>
> Spoke too soon. Looks like this is what I need:
> http://www.codeproject.com/Articles/534/An-Introduction-to-Processes-Asynchronous-Process

You need a loop that run until the PID is invalid. something like:

---
while(true)
{
    Thread.sleep(dur!"msecs"(10));

    // operation on i/o streams
    write(pipes.stdout.readln);

    if (pipes.pid.tryWait.terminated)
        break;
}
---

also note that the piped process needs its whole output to be read before it terminates, otherwise it can stick (never ends).

On Saturday, 9 May 2015 at 18:19:16 UTC, Baz wrote:
> You need a loop that run until the PID is invalid.

You could also call WaitForSingleObject on the process handle
https://msdn.microsoft.com/en-us/library/windows/desktop/ms687032%28v=vs.85%29.aspx

The HANDLE it expects can be gotten from std.process with this
http://dlang.org/phobos/std_process.html#osHandle


But then you'll block for it to end so it probably isn't what you really want...

On Saturday, 9 May 2015 at 13:00:01 UTC, wobbles wrote:
> On Linux, I'm able to edit a file descriptor after I've created it to tell it to read/write asynchronously, I cant seem to find anything similar on windows however.

Asynchronous I/O on Windows is called "Overlapped I/O". It is a bit involved to use though, especially since D by default doesn't come with all the necessary headers. You can download the win32 api bindings or you can just declare the bits as needed.

My terminal emulator uses overlapped I/O and a spawned process (and on Linux, it uses forkpty!) to talk to ssh on Windows.

https://github.com/adamdruppe/terminal-emulator/blob/master/terminalemulator.d

I had to write a function to make an async pipe, then spawn a process using them, then get and send data. I also declared all the needed functions myself.

A lot of code to go through but it is a working example... a few things to look for are MyCreatePipeEx, CreateProcess, the word 'overlapped', ReadFileEx, and the simpledisplay.d library it imports also uses SleepEx which lets other things trigger.