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[ID 20010925.051] <> vs <STDIN> is OS specific

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From:
David Madison
Date:
September 25, 2001 19:30
Subject:
[ID 20010925.051] <> vs <STDIN> is OS specific
Message ID:
200109260229.TAA30137@madison-home.transmeta.com
This is a bug report for perl from perlbug@daveola.com,
generated with the help of perlbug 1.26 running under perl 5.00503.


-----------------------------------------------------------------
[Please enter your report here]

I wrote a simple STDIN inline filter that puts a command in
the path of STDIN.  It sends STDIN to open2, and then takes the
output of that and dups it back to STDIN.

When I then read from <> (as opposed to <STDIN>), I get nothing
on a linux box (tested with 5.005, 5.004, 5.6.0 and 5.6.1), but
it works fine on other OS (at least Solaris).

--------------------------------------------------
use IO::File;
use IPC::Open2;
sub stdin_filter {
  my ($cmd) = @_;
  $pid=open2(\*TMPIN,'<&STDIN',$cmd);
  die("Couldn't fork $!") if $pid == -1;
  open(STDIN,"<&TMPIN");        # Dup back to STDIN
}

stdin_filter("sort");
#while(<STDIN>) { print "new $_"; }	# Works everywhere
while(<>) { print "new $_"; }		# Works if !linux
--------------------------------------------------


[Please do not change anything below this line]
-----------------------------------------------------------------

---
Site configuration information for perl 5.00503:

Configured by root at Mon Aug 30 23:08:56 EDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=linux, osvers=2.2.5-22smp, archname=i386-linux
    uname='linux porky.devel.redhat.com 2.2.5-22smp #1 smp wed jun 2 09:11:51 edt 1999 i686 unknown '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='-O2', gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
    cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    stdchar='char', d_stdstdio=undef, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -ldl -lm -lc -lposix -lcrypt
    libc=, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    

---
@INC for perl 5.00503:
    /usr/lib/perl5/5.00503/i386-linux
    /usr/lib/perl5/5.00503
    /usr/lib/perl5/site_perl/5.005/i386-linux
    /usr/lib/perl5/site_perl/5.005
    .

---
Environment for perl 5.00503:
    HOME=/home/madison
    LANG (unset)
    LANGUAGE (unset)
    LC_ALL=C
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=.:/home/madison/bin/i386-linux-libc6:/home/madison/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/usr/openwin/bin:/usr/sbin:/sbin:/usr/local/sbin:/proj/hw/bin:/proj/hw/bin/i386-linux-libc6:/cad/scripts:/usr/local/contrib/bin:.:/proj/sw/astro/tools/i386-linux-libc6/bin
    PERL_BADLANG (unset)
    SHELL=/bin/tcsh


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