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[perl #69332] :encoding() returns wrong value on eof

From:
Eric Brine
Date:
September 24, 2009 06:36
Subject:
[perl #69332] :encoding() returns wrong value on eof
Message ID:
rt-3.6.HEAD-21832-1253735468-34.69332-75-0@perl.org
# New Ticket Created by  "Eric Brine" 
# Please include the string:  [perl #69332]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=69332 >


This is a bug report for perl from ikegami@adaelis.com,
generated with the help of perlbug 1.39 running under perl 5.10.1.


-----------------------------------------------------------------
[Please describe your issue here]

When using :encoding, read() returns undef at eof rather than zero.

----- BEGIN code -----
#!/usr/bin/perl

use strict;
use warnings;

sub test {
    my ($fh) = @_;
    my $buf = '';
    for (1..3) {
        my $rv = read($fh, $buf, 1, length($buf));
        if (defined($rv)) {
            print("read = $rv\n");
        } else {
            print("read = undef, \$!=$!\n");
        }
    }
}

{ open(my $fh, '<',                      \'ab') or die;  test($fh); }
{ open(my $fh, '<:encoding(iso-8859-1)', \'ab') or die;  test($fh); }
----- END code -----

----- BEGIN output -----
read = 1
read = 1
read = 0

read = 1
read = 1
read = undef, $!=
----- END output -----

(newline added for readability)

I haven't managed to track down the cause.


[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=library
    severity=low
    module=PerlIO::encoding
---
Site configuration information for perl 5.10.1:

Configured by SYSTEM at Mon Aug 24 13:48:02 2009.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration:

  Platform:
    osname=MSWin32, osvers=5.00, archname=MSWin32-x86-multi-thread
    uname=''
    config_args='undef'
    hint=recommended, useposix=true, d_sigaction=undef
    useithreads=define, usemultiplicity=define
    useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cl', ccflags ='-nologo -GF -W3 -MD -Zi -DNDEBUG -O1 -DWIN32
-D_CONSOLE -DNO_STRICT -DHAVE_DES_FCRYPT -DUSE_SITECUSTOMIZE
-DPRIVLIB_LAST_IN_INC -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS
-DUSE_PERLIO -DPERL_MSVCRT_READFIX',
    optimize='-MD -Zi -DNDEBUG -O1',
    cppflags='-DWIN32'
    ccversion='12.00.8804', gccversion='', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=8
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='__int64',
lseeksize=8
    alignbytes=8, prototype=define
  Linker and Libraries:
    ld='link', ldflags ='-nologo -nodefaultlib -debug -opt:ref,icf
-libpath:"C:\progs\perl5101\lib\CORE"  -machine:x86'
    libpth=\lib
    libs=  oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib  netapi32.lib
uuid.lib ws2_32.lib mpr.lib winmm.lib  version.lib odbc32.lib odbccp32.lib
msvcrt.lib
    perllibs=  oldnames.lib kernel32.lib user32.lib gdi32.lib winspool.lib
comdlg32.lib advapi32.lib shell32.lib ole32.lib oleaut32.lib  netapi32.lib
uuid.lib ws2_32.lib mpr.lib winmm.lib  version.lib odbc32.lib odbccp32.lib
msvcrt.lib
    libc=msvcrt.lib, so=dll, useshrplib=true, libperl=perl510.lib
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -debug
-opt:ref,icf  -libpath:"C:\progs\perl5101\lib\CORE"  -machine:x86'

Locally applied patches:
    ACTIVEPERL_LOCAL_PATCHES_ENTRY
    32728 64-bit fix for Time::Local

---
@INC for perl 5.10.1:
    c:/Progs/perl5101/site/lib
    c:/Progs/perl5101/lib
    .

---
Environment for perl 5.10.1:
    HOME (unset)
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)

PATH=c:\bin;c:\progs\perl5101\bin;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\WBEM
    PERL_BADLANG (unset)
    SHELL (unset)



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