seek() on a pipe should return an error, but it doesn't

p5pRT commented 21 years ago

Migrated from rt.perl.org#22087 (status was 'resolved')

Searchable as RT22087$

p5pRT commented 21 years ago

From kenhirsch@myself.com

Created by kenhirsch@myself.com

seek() on a pipe should return an error\, but it doesn't

With ActivePerl 5.8\, this test program: #!perl -w # seektest.pl while (\) { print; if ($. == 3) { if (seek STDIN\, 0\, 0) { print "Seek succeeded\n"; } else { print "Seek failed: $!\n"; } } } print "END\n";

when run as follows type testfile | perl seektest.pl

With testfile containing Line 1 Line 2 Line 3 Line 4 Line 5 Line 6

The output is (INCORRECT): Line 1 Line 2 Line 3 Seek succeeded END

When run with cygwin perl\, the output is (CORRECT): Line 1 Line 2 Line 3 Seek failed: Illegal seek Line 4 Line 5 Line 6 END

Perl Info

``` Flags: category=core severity=medium Site configuration information for perl v5.8.0: Configured by ActiveState at Tue Feb 4 18:07:44 2003. Summary of my perl5 (revision 5 version 8 subversion 0) configuration: Platform: osname=MSWin32, osvers=4.0, archname=MSWin32-x86-multi-thread uname='' config_args='undef' hint=recommended, useposix=true, d_sigaction=undef usethreads=undef use5005threads=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_FCR YPT -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX' , optimize='-MD -Zi -DNDEBUG -O1', cppflags='-DWIN32' ccversion='', gccversion='', gccosandvers='' intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234 d_longlong=undef, longlongsize=8, d_longdbl=define, longdblsize=10 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 -release -libpath:"C:\Perl\lib\CORE" -machine:x86' libpth="C:\Perl\lib\CORE" 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 wsock32.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 wsock32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib msvcrt.lib libc=msvcrt.lib, so=dll, useshrplib=yes, libperl=perl58.lib gnulibc_version='undef' Dynamic Linking: dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' ' cccdlflags=' ', ddlflags='-dll -nologo -nodefaultlib -release -libpath:"C:\Perl\lib\CORE" -machine :x86' Locally applied patches: ACTIVEPERL_LOCAL_PATCHES_ENTRY @INC for perl v5.8.0: c:/Perl/lib c:/Perl/site/lib . Environment for perl v5.8.0: CYGWIN=tty HOME=c:\home\Ken LANG (unset) LANGUAGE (unset) LD_LIBRARY_PATH (unset) LOGDIR (unset) PATH=c:\perl\bin;c:\usr\local\bin;c:\\bin;c:\bin;c:\J2SDK_Forte\jdk1.4.0\bin;c:\Pyth on21\;c:\Perl\bin\;c:\bin;c:\vim\vim61;c:\WINDOWS\system32;c:\WINDOWS;c:\WINDOWS\Sys tem32\Wbem;c:\Program Files\Common Files\Adaptec Shared\System;c:\Program Files\Microsoft SDK\Bin\;c:\Program Files\Microsoft SDK\Bin\WinNT\;c:\Program Files\VSE\win;c:\Program Files\Microsoft Visual Studio\Common\Tools\WinNT;c:\Program Files\Microsoft Visual Studio\Common\MSDev98\Bin;c:\Program Files\Microsoft Visual Studio\Common\Tools;c:\Program Files\Microsoft Visual Studio\VC98\bin;c:\Program Files\Microsoft SDK\Bin\;c:\Program Files\Microsoft SDK\Bin\WinNT\;. PERL_BADLANG (unset) SHELL (unset) ```

p5pRT commented 21 years ago

From nick.ing-simmons@elixent.com

Ken Hirsch \perl5\-porters@perl\.org writes:

# New Ticket Created by Ken Hirsch # Please include the string: [perl #22087] # in the subject line of all future correspondence about this issue. # \<URL: http://rt.perl.org/rt2/Ticket/Display.html?id=22087 >

This is a bug report for perl from kenhirsch@myself.com\, generated with the help of perlbug 1.34 running under perl v5.8.0.

----------------------------------------------------------------- [Please enter your report here] seek() on a pipe should return an error\,

Says who? ;-)

This probably _is_ a bug\, but if the file position is still in the buffer I think the run-time is a liberty to move it back and succeed.

I ask your reason because one of features of "sfio" I had considered copying for PerlIO was its ability to make any file-type "seekable" (which it does by creating a temp file containing an "image" of what is read/written to the stream).

but it doesn't

But does a subsequent read() return the original posn 0 data correctly?

With ActivePerl 5.8\, this test program: #!perl -w # seektest.pl while (\) { print; if ($. == 3) { if (seek STDIN\, 0\, 0) { print "Seek succeeded\n"; } else { print "Seek failed: $!\n"; } } } print "END\n";

when run as follows type testfile | perl seektest.pl

With testfile containing Line 1 Line 2 Line 3 Line 4 Line 5 Line 6

The output is (INCORRECT): Line 1 Line 2 Line 3 Seek succeeded END

When run with cygwin perl\, the output is (CORRECT): Line 1 Line 2 Line 3 Seek failed: Illegal seek Line 4 Line 5 Line 6 END

[Please do not change anything below this line] ----------------------------------------------------------------- --- Flags: category=core severity=medium --- Site configuration information for perl v5.8.0:

Configured by ActiveState at Tue Feb 4 18:07:44 2003.

Summary of my perl5 (revision 5 version 8 subversion 0) configuration: Platform: osname=MSWin32\, osvers=4.0\, archname=MSWin32-x86-multi-thread uname='' config_args='undef' hint=recommended\, useposix=true\, d_sigaction=undef usethreads=undef use5005threads=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_FCR YPT -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS -DUSE_PERLIO -DPERL_MSVCRT_READFIX' \, optimize='-MD -Zi -DNDEBUG -O1'\, cppflags='-DWIN32' ccversion=''\, gccversion=''\, gccosandvers='' intsize=4\, longsize=4\, ptrsize=4\, doublesize=8\, byteorder=1234 d_longlong=undef\, longlongsize=8\, d_longdbl=define\, longdblsize=10 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 -release -libpath:"C:\Perl\lib\CORE" -machine:x86' libpth="C:\Perl\lib\CORE" 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 wsock32.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 wsock32.lib mpr.lib winmm.lib version.lib odbc32.lib odbccp32.lib msvcrt.lib libc=msvcrt.lib\, so=dll\, useshrplib=yes\, libperl=perl58.lib gnulibc_version='undef' Dynamic Linking: dlsrc=dl_win32.xs\, dlext=dll\, d_dlsymun=undef\, ccdlflags=' ' cccdlflags=' '\, ddlflags='-dll -nologo -nodefaultlib -release -libpath:"C:\Perl\lib\CORE" -machine :x86'

Locally applied patches: ACTIVEPERL_LOCAL_PATCHES_ENTRY

--- @INC for perl v5.8.0: c:/Perl/lib c:/Perl/site/lib .

--- Environment for perl v5.8.0: CYGWIN=tty HOME=c:\home\Ken LANG (unset) LANGUAGE (unset) LD_LIBRARY_PATH (unset) LOGDIR (unset)

PATH=c:\perl\bin;c:\usr\local\bin;c:\\bin;c:\bin;c:\J2SDK_Forte\jdk1.4.0\bin;c:\Pyth on21\;c:\Perl\bin\;c:\bin;c:\vim\vim61;c:\WINDOWS\system32;c:\WINDOWS;c:\WINDOWS\Sys tem32\Wbem;c:\Program Files\Common Files\Adaptec Shared\System;c:\Program Files\Microsoft SDK\Bin\;c:\Program Files\Microsoft SDK\Bin\WinNT\;c:\Program Files\VSE\win;c:\Program Files\Microsoft Visual Studio\Common\Tools\WinNT;c:\Program Files\Microsoft Visual Studio\Common\MSDev98\Bin;c:\Program Files\Microsoft Visual Studio\Common\Tools;c:\Program Files\Microsoft Visual Studio\VC98\bin;c:\Program Files\Microsoft SDK\Bin\;c:\Program Files\Microsoft SDK\Bin\WinNT\;. PERL_BADLANG (unset) SHELL (unset) -- Nick Ing-Simmons http://www.ni-s.u-net.com/

p5pRT commented 21 years ago

From kenhirsch@myself.com

From: "Nick Ing-Simmons (via RT)" \perlbug\-followup@perl\.org

I ask your reason because one of features of "sfio" I had considered copying for PerlIO was its ability to make any file-type "seekable" (which it does by creating a temp file containing an "image" of what is read/written to the stream).

but it doesn't

But does a subsequent read() return the original posn 0 data correctly?

No\, it returns eof

p5pRT commented 21 years ago

From nick@ing-simmons.net

This bug is due to Win32's lseek() not giving an error (or doing the right thing). It is fixed by fix to bugs 21717 and 22140 - which causes PerlIOUnix_seek to return error by itself if stream is not a "regular file".

p5pRT commented 21 years ago

nick@ing-simmons.net - Status changed from 'new' to 'resolved'

Perl / perl5