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Date: Thu, 19 Apr 2012 17:00:28 +0200
From: Peter Rosin <peda AT lysator DOT liu DOT se>
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Subject: Re: 1.7.10->1.7.13 : output from .NET programs does not get through pipeline to a visual c++ program
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On 2012-04-19 16:14, Christopher Faylor wrote:
> On Thu, Apr 19, 2012 at 12:56:33PM +0100, somebody wrote:
>> Hi all,
>>
>> This started in 1.7.10 and I thought this may be fixed in 1.7.12 due
>> to emails in the mailing list:
>> http://sourceware.org/ml/cygwin/2012-03/msg00666.html
>>
>> But there still seems to be a problem piping from a .net console
>> application to a visual c++ console application.
>>
>> Using the following simple C# program complied using "csc /optimize
>> /target:exe /out:./consoleout.exe Program.cs"
>>
>>>>>> Begin Program.cs
>> namespace consoleout
>> {
>>    using System;
>>
>>    internal static class Program
>>    {
>>        private static void Main(string[] args)
>>        {
>>            foreach (var arg in args) {
>>                Console.Out.WriteLine(arg);
>>            }
>>        }
>>    }
>> }
>> <<<< End Program.cs
>>
>> I can use this to output to cygwin exes OK
>> $ ./consoleout.exe Hello There | cat
>> Hello
>> There
>> $ ./consoleout.exe Hello There | grep ll
>> 1:Hello
>> $
>>
>> I also created a visual c++ executable like the simple one below
>> compiled with "cl /EHs readin.cxx /link"
>>
>>>>>> Begin readin.cxx
>> #include <string>
>> #include <iostream>
>>
>> int
>> main(int argc, char** argv)
>> {
>>    static_cast<void>(argc);
>>    static_cast<void>(argv);
>>    std::string buf;
>>    buf.reserve(1024);
>>    while (std::getline(std::cin, buf, '\n')) {
>>        std::cout << buf << '\n';
>>    }
>>    return EXIT_SUCCESS;
>> }
>> <<<< End readin.cxx
>>
>> I can use this to output anything read in
>> $ echo Hello | ./readin.exe
>> Hello
>> $ cat 'readin.cxx' | ./readin.exe
>> #include <string>
>> #include <iostream>
>>
>> int
>> main(int argc, char** argv)
>> {
>>    static_cast<void>(argc);
>>    static_cast<void>(argv);
>>    std::string buf;
>>    buf.reserve(1024);
>>    while (std::getline(std::cin, buf, '\n')) {
>>        std::cout << buf << '\n';
>>    }
>>    return EXIT_SUCCESS;
>> }
>> $
>>
>> But when combining the two, nothing happens.
>> $ ./consoleout.exe Hello There | ./readin.exe
>> $
>>
>> It "seems" as though the console out from the .net is not being
>> correctly piped through to a vc++ program. I know that is a strange
>> defect given all the other combinations work.
>>
>> The reverse works i.e. output from a visual c++ console application is
>> piped correctly to a .net console application.
>>
>> This worked prior to 1.7.10 (1.7.9 and before).
>>
>> I am sorry that I cannot point to an area in the Cygwin code or
>> suggest a fix, but I am hoping this is enough of a description to help
>> someone find out what the issue is.
> 
> Sorry but I'm not going to set up a .NET development environment to
> figure out a problem.  If someone else wants to provide a clue as
> to what's going on, I'd appreciate it.

I'll bite, and it WJFFM...

$ ./consoleout hello world | ./readin
hello
world
$ uname -a
CYGWIN_NT-6.1-WOW64 PEDA-PC 1.7.13(0.260/5/3) 2012-04-05 12:43 i686 Cygwin

To stress it a tiny bit more:
$ ./consoleout hello world | ./readin | ./readin | ./readin | ./readin
hello
world
$ ./consoleout hello world | ./readin | ./readin | grep rl | ./readin | ./readin
world

Question for the OP: Does the pipe work from a cmd prompt?

Cheers,
Peter

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