kartlee1 has asked for the wisdom of the Perl Monks concerning the following question:

Hi People, I have an environment variable set in Windows as TEST=abc£ which uses Windows-1252 code page. Now when I run a perl program - 'test.pl', this environment value comes properly. When I call another perl code - 'test2.pl' from 'test1.pl' either by system(..) or Win32::process(..), the environment comes garbled. Can someone provide information why this could be and way to resolve it? The version of perl I am using is 5.8. If my understanding is right, perl internally uses 'utf-8', so the initial process - 'test1.pl' received it right from windows1252->utf-8. When we call another process, should we convert back to windows 1252 code page? -Kartlee

Replies are listed 'Best First'.
Re: Perl character encoding
by cdarke (Prior) on Mar 13, 2010 at 16:13 UTC
    I just tried this on 5.10.1 from cmd.exe and I got no difference between the two processes. Of course this is assuming that the text I see on my browser is exactly the same as you mean, since translation can occur there as well.

    The cmd.exe did not display the £ correctly, it gave:
    test1.pl: <abcú>
test2.pl: <abcú>

    [download]
    You do not say exactly what "garbled" is. It might help if you display the characters in hex. printf "%x", $ENV{TEST}; before and after you pass them through the environment block to see what the change really is.

    I am interested in your perception of perl translating from Windows 1252 to utf-8 and back - can you cite the reference where you read that?
[reply]
[d/l]
[select]

      Console applications and windowed applications* use different encodings, often cp1252 and cp850. The cp1252 encoding of "£" is the same as the cp850 encoding of "ú". 

         Unicode  cp1252   cp850
£  U+00A3   A3=0243  C9=0311
ú  U+00FA   FA=0372  A3=0243

      [download]

      * — I'm not sure what the actual distinction is.

[reply]
[d/l]
      
test=c:\\temp\\abc£

test.pl
-------

use Devel::Peek; 
print Dump $ENV{"TEST"}; 
system("perl.exe c:\\temp\\test1.pl");

test1.pl
--------

use Devel::Peek; 
print Dump $ENV{"TEST"}; 


Running test.pl returns:


SV = PVMG(0x1a22dcc) at 0x356fd4
  REFCNT = 1
  FLAGS = (SMG,RMG,POK,pPOK)
  IV = 0
  NV = 0
  PV = 0x1a2f4a4 "c:\\temp\\abc\243"\0
  CUR = 12
  LEN = 16
  MAGIC = 0x1a2f4cc
    MG_VIRTUAL = &PL_vtbl_envelem
    MG_TYPE = PERL_MAGIC_envelem(e)
    MG_LEN = 17
    MG_PTR = 0x1a2f4fc "TEST"
SV = PVMG(0x1a22dcc) at 0x356fd4
  REFCNT = 1
  FLAGS = (SMG,RMG,POK,pPOK)
  IV = 0
  NV = 0
  PV = 0x1a2f4bc "c:\\temp\\abc\234"\0
  CUR = 12
  LEN = 16
  MAGIC = 0x1a2f4e4
    MG_VIRTUAL = &PL_vtbl_envelem
    MG_TYPE = PERL_MAGIC_envelem(e)
    MG_LEN = 17
    MG_PTR = 0x1a2f514 "TEST"

      [download]
      -Kartlee
[reply]
[d/l]

        Both contain the same still-encoded string. Your test doesn't demonstrate the corruption you mentioned.

        By the way, print Dump should be just Dump

[reply]
[d/l]
[select]
Re: Perl character encoding
by BrowserUk (Patriarch) on Mar 13, 2010 at 19:52 UTC

    Intriguing. I see a similar difference: 

    C:\test>set TEST=abc£
C:\test>echo %TEST%
abc£

perl -MWin32::Console -E"say '1:', $ENV{TEST};say Win32::Console::Outp
+utCP; 
system q[perl -MWin32::Console -E\"say '2:', $ENV{TEST};
     say Win32::Console::OutputCP;\"]"
1:abcú
850
2:abc£
850

    [download]

    And the difference seems to be internal to Perl somehow.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]
[d/l]
Re: Perl character encoding
by youlose (Scribe) on Mar 15, 2010 at 10:59 UTC
    you need to: 1. decode string from CP1252 2. encode it to CP850
[reply]

Back to Seekers of Perl Wisdom