www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.learn - eof

reply "lx" <zdhtlixin 126.com> writes:
Hi,everyone,
I am learning D.I installed a plugin-visusl D to visual studio 
2008.I am very confused that ctrl+z didn't teminate the input of 
console,it result in a dead loop.When reading from a txt file,a 
extra line will be read and usually it result in a wrong 
result.Is there anyone who has experienced such a situation and 
can tell me what I should pay attention to.
Thanks a lot.
lx
Jun 24 2013
parent reply "bearophile" <bearophileHUGS lycos.com> writes:
lx:


 I am very confused that ctrl+z didn't teminate the input of 
 console,it result in a dead loop.


I think this is a library bug, I noticed it some times, but I 
didn't file it. Maybe it's worth filing in Bugzilla.




 When reading from a txt file,a extra line will be read and 
 usually it result in a wrong result.


Can you show the code?

Bye,
bearophile
Jun 24 2013
parent reply "bearophile" <bearophileHUGS lycos.com> writes:
 I am very confused that ctrl+z didn't teminate the input of 
 console,it result in a dead loop.


 I think this is a library bug, I noticed it some times, but I 
 didn't file it. Maybe it's worth filing in Bugzilla.


I have added this bug report, is this the issue you are 
seeing/having?

http://d.puremagic.com/issues/show_bug.cgi?id=10467

Bye,
bearophile
Jun 24 2013
next sibling parent reply "monarch_dodra" <monarchdodra gmail.com> writes:
On Monday, 24 June 2013 at 21:13:31 UTC, bearophile wrote:

 I am very confused that ctrl+z didn't teminate the input of 
 console,it result in a dead loop.


 I think this is a library bug, I noticed it some times, but I 
 didn't file it. Maybe it's worth filing in Bugzilla.


 I have added this bug report, is this the issue you are 
 seeing/having?

 http://d.puremagic.com/issues/show_bug.cgi?id=10467

 Bye,
 bearophile


I don't think this is a bug (I replied on the bug report): 
terminating the stream doesn't mean terminating the program, and 
if the program doesn't know how to handle a closed/eof/error'd 
stdin, it will just loop...

This FAQ link explains it pretty well for C++, which is pretty 
much the same thing as in D:
http://www.parashift.com/c++-faq/stream-input-failure.html
(the next few points are relevant too).

We could argue the design isn't optimal, yes, but it's not bugged.
Jun 24 2013
parent "bearophile" <bearophileHUGS lycos.com> writes:
monarch_dodra:


 I don't think this is a bug


I see. Then lx will have to explain the problem better.



 (I replied on the bug report):


I have given an answer, comparing to Python. I think the current 
Phobos behavour is bad.

Bye,
bearophile
Jun 24 2013
prev sibling parent reply "lx" <zdhtlixin 126.com> writes:
On Monday, 24 June 2013 at 21:13:31 UTC, bearophile wrote:

 I am very confused that ctrl+z didn't teminate the input of 
 console,it result in a dead loop.


 I think this is a library bug, I noticed it some times, but I 
 didn't file it. Maybe it's worth filing in Bugzilla.


 I have added this bug report, is this the issue you are 
 seeing/having?

 http://d.puremagic.com/issues/show_bug.cgi?id=10467

 Bye,
 bearophile


I read those information and yes,it is the issue I am having.I 
should have handled it in right way.Ctrl+z seems close the 
stream.So,if I want to input another batch of data,it became 
impossilbe.So,how to reopen the stream again to allow me to input 
another batch of data?

And,another problem:if I input ctrl+c,the code will terminate 
abnormally.Why this happened?
Thanks.
lx
Jun 25 2013
next sibling parent reply =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 06/25/2013 09:26 PM, lx wrote:


 Ctrl+z seems close the stream.So,if I want
 to input another batch of data,it became impossilbe.So,how to reopen the
 stream again to allow me to input another batch of data?


Making a copy of stdin works on Linux (where the stream is terminated by 
Ctrl-D in the console):

import std.stdio;
import std.algorithm;

void main()
{
     auto stdin_dup = stdin;

     stdin
         .byLine(KeepTerminator.yes)
         .copy(stdout.lockingTextWriter);

     writeln("done");

     stdin_dup
         .byLine(KeepTerminator.yes)
         .copy(stdout.lockingTextWriter);

     writeln("done again");
}

Ali
Jun 25 2013
parent reply "lx" <zdhtlixin 126.com> writes:
On Wednesday, 26 June 2013 at 04:46:32 UTC, Ali Çehreli wrote:

 On 06/25/2013 09:26 PM, lx wrote:


 Ctrl+z seems close the stream.So,if I want
 to input another batch of data,it became impossilbe.So,how to


 reopen the

 stream again to allow me to input another batch of data?


 Making a copy of stdin works on Linux (where the stream is 
 terminated by Ctrl-D in the console):

 import std.stdio;
 import std.algorithm;

 void main()
 {
     auto stdin_dup = stdin;

     stdin
         .byLine(KeepTerminator.yes)
         .copy(stdout.lockingTextWriter);

     writeln("done");

     stdin_dup
         .byLine(KeepTerminator.yes)
         .copy(stdout.lockingTextWriter);

     writeln("done again");
 }

 Ali


Hi,Ali,I tried those codes,it doesn't work under win7.The result 
is
"done again" will follow "done",without giving me any chance to 
input.
lx
Jun 26 2013
parent "lx" <zdhtlixin 126.com> writes:
On Wednesday, 26 June 2013 at 13:45:41 UTC, lx wrote:

 On Wednesday, 26 June 2013 at 04:46:32 UTC, Ali Çehreli wrote:

 On 06/25/2013 09:26 PM, lx wrote:


 Ctrl+z seems close the stream.So,if I want
 to input another batch of data,it became impossilbe.So,how to


 reopen the

 stream again to allow me to input another batch of data?


 Making a copy of stdin works on Linux (where the stream is 
 terminated by Ctrl-D in the console):

 import std.stdio;
 import std.algorithm;

 void main()
 {
    auto stdin_dup = stdin;

    stdin
        .byLine(KeepTerminator.yes)
        .copy(stdout.lockingTextWriter);

    writeln("done");

    stdin_dup
        .byLine(KeepTerminator.yes)
        .copy(stdout.lockingTextWriter);

    writeln("done again");
 }

Ali




  Hi,Ali,I tried those codes,it doesn't work under win7.The
  result is
"done again" will follow "done",without giving me any chance to
  input again after I enter ctrl-z .
  lx
Jun 26 2013
prev sibling parent =?UTF-8?B?QWxpIMOHZWhyZWxp?= <acehreli yahoo.com> writes:
On 06/25/2013 09:26 PM, lx wrote:


 I input ctrl+c,the code will terminate
 abnormally.Why this happened?


Ctrl-C appears as SIGINT under POSIX systems. You need to register a 
handler for that signal:

import std.stdio;
import std.string;
import core.sys.posix.signal;

bool isDone = false;

extern(C) void mySIGINThandler(int) nothrow  system
{
     isDone = true;
}

void main()
{
     signal(SIGINT, &mySIGINThandler);

     while (true) {
         string line = chomp(readln());

         if (stdin.eof() || isDone) {
             break;

         } else {
             writefln("Nice line: %s", line);
         }
     }
}

Ali
Jun 25 2013