Re: [GHC] #3256: Extra EOT from NoBuffering mode in emacs
#3256: Extra EOT from NoBuffering mode in emacs
-+--
Reporter: judah |Owner:
Type: bug | Status: closed
Priority: normal|Milestone: 6.10.4
Component: Compiler | Version: 6.10.3
Severity: normal| Resolution: invalid
Keywords:| Difficulty: Unknown
Testcase:| Os: Linux
Architecture: Unknown/Multiple |
-+--
Changes (by simonmar):
* status: new = closed
* resolution: = invalid
Comment:
As far as I can tell, this is not a bug in GHC. The same behaviour can be
replicated with a C program:
{{{
#include termios.h
#include unistd.h
#include stdlib.h
main()
{
char buf[1024];
struct termios termios;
int r;
tcgetattr(0,termios);
termios.c_lflag = ~ECHO;
termios.c_lflag = ~ICANON;
termios.c_cc[VMIN] = 1;
termios.c_cc[VTIME] = 0;
tcsetattr(0,TCSANOW,termios);
do {
r = read(0, buf, 1024);
write(1, buf, r);
} while (r != 0);
exit(0);
}
}}}
If you paste a line of 255 x's to the C program in emacs, you'll see a
`^D` character inserted in the output, in exactly the same way as with the
Haskell program. This appears to be something that emacs is doing when
stdin has ICANON unset.
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3256#comment:3
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Re: [GHC] #3256: Extra EOT from NoBuffering mode in emacs
#3256: Extra EOT from NoBuffering mode in emacs -+-- Reporter: judah |Owner: Type: bug | Status: new Priority: normal|Milestone: 6.10.4 Component: Compiler | Version: 6.10.3 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase:| Os: Linux Architecture: Unknown/Multiple | -+-- Changes (by nad): * cc: nad (added) -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3256#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[GHC] #3256: Extra EOT from NoBuffering mode in emacs
#3256: Extra EOT from NoBuffering mode in emacs
---+
Reporter: judah | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 6.10.3 | Severity: normal
Keywords: | Testcase:
Os: Linux | Architecture: Unknown/Multiple
---+
Compile the following program:
{{{
import System.IO
main = hSetBuffering stdin NoBuffering getLine = print
}}}
Then start emacs, run M-x shell, and start the above program. Paste the
output of {{{replicate 252 'x'}}} as input and press return. An extra EOT
character is added to the end of the input:
{{{
$ ./foo
a\
aa\
a
\aaa\
aa\
aaa\\\
EOT
}}}
I can make this happen consistently using Ubuntu 8.04.2 and emacs-22.1.1.
I can't reproduce it on OS X or outside of emacs's shell.
This was originally reported on the Haskeline bug tracker, as it affects
ghci/haskeline: http://trac.haskell.org/haskeline/ticket/79 . From that
ticket:
The problem seems to be that Emacs does not send all of the input at
once:
If STRING is more than 500 characters long, it is sent in several
bunches. This may happen even for shorter strings.
(From the documentation of process-send-string in GNU Emacs 23.0.93.1.)
See also the following message:
http://thread.gmane.org/gmane.comp.lang.haskell.glasgow.user/15591/focus=15632.
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/3256
GHC http://www.haskell.org/ghc/
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