"$#++" fails under ActiveState 5.6

[p5pRT]

Migrated from rt.perl.org#3325 (status was 'resolved')

Searchable as RT3325$

[p5pRT]

From thomason@its.caltech.edu

-----BEGIN PGP SIGNED MESSAGE-----
Hash​: SHA1

This is a bug report for perl from Adam Thomason@​its.caltech.edu,
generated with the help of perlbug 1.28 running under perl v5.6.0.

- -----------------------------------------------------------------

Under ActiveState Perl 5.6, the statement "$#++" fails, e.g.

  H​:\>perl -e "$#++;"
  syntax error at -e line 1, near "+;"
  Execution of -e aborted due to compilation errors.

However, "++$#;" does just fine. This was originally noticed
in an obfuscation post at
  http​://www.perlmonks.org/index.pl?node_id=16103
I tested the obfuscated code on SunOS and RH Linux running
5.005, and both didn't have a problem with $#++. Another user
confirmed that his Linux with Perl 5.6 failed with the same
problem. So the problem appears confined the 5.6, though still
multiplatform.

Of course, $# is deprecated anyhow; anybody using $# and 5.6
at the same time is probably asking to get bit ;-).

Perl Info

- ---
Flags:
    category=core
    severity=low
- ---
Site configuration information for perl v5.6.0:

Configured by Adam Thomason at Fri Mar 24 12:36:06 2000.

Summary of my perl5 (revision 5 version 6 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=undef d_sfio=undef uselargefiles=undef 
    use64bitint=undef use64bitall=undef uselongdouble=undef
usesocks=undef
  Compiler:
    cc='cl', optimize='-O1 -MD -DNDEBUG', gccversion=
    cppflags='-DWIN32'
    ccflags ='-O1 -MD -DNDEBUG -DWIN32 -D_CONSOLE -DNO_STRICT
- -DHAVE_DES_FCRYPT  -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS
- -DPERL_MSVCRT_READFIX'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=undef, longlongsize=8, d_longdbl=define,
longdblsize=10
    ivtype='long', ivsize=4, nvtype='double', nvsize=8,
Off_t='off_t', lseeksize=4
    alignbytes=8, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='link', ldflags ='-nologo -nodefaultlib -release 
- -libpath:"H:\Perl\lib\CORE"  -machine:x86'
    libpth="H:\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
    libc=msvcrt.lib, so=dll, useshrplib=yes, libperl=perl56.lib
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -release 
- -libpath:"H:\Perl\lib\CORE"  -machine:x86'

Locally applied patches:
    ACTIVEPERL_LOCAL_PATCHES_ENTRY

- ---
@INC for perl v5.6.0:
    H:/Perl/lib
    H:/Perl/site/lib
    .

- ---
Environment for perl v5.6.0:
    HOME (unset)
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
   
PATH=H:\Perl\bin\;H:\WINNT\system32;H:\WINNT;H:\WINNT\system32\WBEM;C:
\WinNt\System32;H:\Program Files\Network Associates\PGPNT;H:\Program
Files\Common Files\MDL Shared\ISIS
    PERL_BADLANG (unset)
    SHELL (unset)

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[p5pRT]

From [Unknown Contact. See original ticket]

-----BEGIN PGP SIGNED MESSAGE-----
Hash​: SHA1

This is a bug report for perl from Adam Thomason@​its.caltech.edu,
generated with the help of perlbug 1.28 running under perl v5.6.0.

- -----------------------------------------------------------------

Under ActiveState Perl 5.6, the statement "$#++" fails, e.g.

  H​:\>perl -e "$#++;"
  syntax error at -e line 1, near "+;"
  Execution of -e aborted due to compilation errors.

However, "++$#;" does just fine. This was originally noticed
in an obfuscation post at
  http​://www.perlmonks.org/index.pl?node_id=16103
I tested the obfuscated code on SunOS and RH Linux running
5.005, and both didn't have a problem with $#++. Another user
confirmed that his Linux with Perl 5.6 failed with the same
problem. So the problem appears confined the 5.6, though still
multiplatform.

Of course, $# is deprecated anyhow; anybody using $# and 5.6
at the same time is probably asking to get bit ;-).

Perl Info

- ---
Flags:
    category=core
    severity=low
- ---
Site configuration information for perl v5.6.0:

Configured by Adam Thomason at Fri Mar 24 12:36:06 2000.

Summary of my perl5 (revision 5 version 6 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=undef d_sfio=undef uselargefiles=undef 
    use64bitint=undef use64bitall=undef uselongdouble=undef
usesocks=undef
  Compiler:
    cc='cl', optimize='-O1 -MD -DNDEBUG', gccversion=
    cppflags='-DWIN32'
    ccflags ='-O1 -MD -DNDEBUG -DWIN32 -D_CONSOLE -DNO_STRICT
- -DHAVE_DES_FCRYPT  -DPERL_IMPLICIT_CONTEXT -DPERL_IMPLICIT_SYS
- -DPERL_MSVCRT_READFIX'
    stdchar='char', d_stdstdio=define, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=undef, longlongsize=8, d_longdbl=define,
longdblsize=10
    ivtype='long', ivsize=4, nvtype='double', nvsize=8,
Off_t='off_t', lseeksize=4
    alignbytes=8, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='link', ldflags ='-nologo -nodefaultlib -release 
- -libpath:"H:\Perl\lib\CORE"  -machine:x86'
    libpth="H:\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
    libc=msvcrt.lib, so=dll, useshrplib=yes, libperl=perl56.lib
  Dynamic Linking:
    dlsrc=dl_win32.xs, dlext=dll, d_dlsymun=undef, ccdlflags=' '
    cccdlflags=' ', lddlflags='-dll -nologo -nodefaultlib -release 
- -libpath:"H:\Perl\lib\CORE"  -machine:x86'

Locally applied patches:
    ACTIVEPERL_LOCAL_PATCHES_ENTRY

- ---
@INC for perl v5.6.0:
    H:/Perl/lib
    H:/Perl/site/lib
    .

- ---
Environment for perl v5.6.0:
    HOME (unset)
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
   
PATH=H:\Perl\bin\;H:\WINNT\system32;H:\WINNT;H:\WINNT\system32\WBEM;C:
\WinNt\System32;H:\Program Files\Network Associates\PGPNT;H:\Program
Files\Common Files\MDL Shared\ISIS
    PERL_BADLANG (unset)
    SHELL (unset)

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iQA/AwUBOTnS383ZgNf94XZ3EQIDOgCg0E7XjZLcaWpa2rHZYppqcQi+H94AoOuz
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[p5pRT]

From @ysth

This is a bug report for perl from Adam Thomason@​its.caltech.edu,
generated with the help of perlbug 1.28 running under perl v5.6.0.

- -----------------------------------------------------------------

Under ActiveState Perl 5.6, the statement "$#++" fails, e.g.

H​:\>perl -e "$#++;"
syntax error at -e line 1, near "+;"
Execution of -e aborted due to compilation errors.

However, "++$#;" does just fine. This was originally noticed
in an obfuscation post at
http​://www.perlmonks.org/index.pl?node_id=16103
I tested the obfuscated code on SunOS and RH Linux running
5.005, and both didn't have a problem with $#++. Another user
confirmed that his Linux with Perl 5.6 failed with the same
problem. So the problem appears confined the 5.6, though still
multiplatform.

Of course, $# is deprecated anyhow; anybody using $# and 5.6
at the same time is probably asking to get bit ;-).

Try​: perl -we "$# ++;";
if you actually want to use $#.

perl -MO=Deparse -we "print $#++0"
reveals that this is parsed as​: print $#+ + 0

$#++ is the last index of @​+ ("$#+") added to something. The syntax
error goes away if you supply a second addend.