perlebcdic.1

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Obviously the first of these will fail to distinguish most \s-1ASCII\s0 machines
from either a \s-1CCSID\s0 0037, a 1047, or a POSIX-BC \s-1EBCDIC\s0 machine since \*(L"\er\*(R" eq 
chr(13) under all of those coded character sets.  But note too that 
because \*(L"\en\*(R" is chr(13) and \*(L"\er\*(R" is chr(10) on the MacIntosh (which is an 
\&\s-1ASCII\s0 machine) the second \f(CW$is_ascii\fR test will lead to trouble there.
.PP
To determine whether or not perl was built under an \s-1EBCDIC\s0 
code page you can use the Config module like so:
.PP
.Vb 2
\&    use Config;
\&    $is_ebcdic = $Config{\*(Aqebcdic\*(Aq} eq \*(Aqdefine\*(Aq;
.Ve
.SH "CONVERSIONS"
.IX Header "CONVERSIONS"
.Sh "tr///"
.IX Subsection "tr///"
In order to convert a string of characters from one character set to 
another a simple list of numbers, such as in the right columns in the
above table, along with perl's tr/// operator is all that is needed.  
The data in the table are in \s-1ASCII\s0 order hence the \s-1EBCDIC\s0 columns 
provide easy to use \s-1ASCII\s0 to \s-1EBCDIC\s0 operations that are also easily 
reversed.
.PP
For example, to convert \s-1ASCII\s0 to code page 037 take the output of the second 
column from the output of recipe 0 (modified to add \e\e characters) and use 
it in tr/// like so:
.PP
.Vb 10
\&    $cp_037 = 
\&    \*(Aq\e000\e001\e002\e003\e234\e011\e206\e177\e227\e215\e216\e013\e014\e015\e016\e017\*(Aq .
\&    \*(Aq\e020\e021\e022\e023\e235\e205\e010\e207\e030\e031\e222\e217\e034\e035\e036\e037\*(Aq .
\&    \*(Aq\e200\e201\e202\e203\e204\e012\e027\e033\e210\e211\e212\e213\e214\e005\e006\e007\*(Aq .
\&    \*(Aq\e220\e221\e026\e223\e224\e225\e226\e004\e230\e231\e232\e233\e024\e025\e236\e032\*(Aq .
\&    \*(Aq\e040\e240\e342\e344\e340\e341\e343\e345\e347\e361\e242\e056\e074\e050\e053\e174\*(Aq .
\&    \*(Aq\e046\e351\e352\e353\e350\e355\e356\e357\e354\e337\e041\e044\e052\e051\e073\e254\*(Aq .
\&    \*(Aq\e055\e057\e302\e304\e300\e301\e303\e305\e307\e321\e246\e054\e045\e137\e076\e077\*(Aq .
\&    \*(Aq\e370\e311\e312\e313\e310\e315\e316\e317\e314\e140\e072\e043\e100\e047\e075\e042\*(Aq .
\&    \*(Aq\e330\e141\e142\e143\e144\e145\e146\e147\e150\e151\e253\e273\e360\e375\e376\e261\*(Aq .
\&    \*(Aq\e260\e152\e153\e154\e155\e156\e157\e160\e161\e162\e252\e272\e346\e270\e306\e244\*(Aq .
\&    \*(Aq\e265\e176\e163\e164\e165\e166\e167\e170\e171\e172\e241\e277\e320\e335\e336\e256\*(Aq .
\&    \*(Aq\e136\e243\e245\e267\e251\e247\e266\e274\e275\e276\e133\e135\e257\e250\e264\e327\*(Aq .
\&    \*(Aq\e173\e101\e102\e103\e104\e105\e106\e107\e110\e111\e255\e364\e366\e362\e363\e365\*(Aq .
\&    \*(Aq\e175\e112\e113\e114\e115\e116\e117\e120\e121\e122\e271\e373\e374\e371\e372\e377\*(Aq .
\&    \*(Aq\e134\e367\e123\e124\e125\e126\e127\e130\e131\e132\e262\e324\e326\e322\e323\e325\*(Aq .
\&    \*(Aq\e060\e061\e062\e063\e064\e065\e066\e067\e070\e071\e263\e333\e334\e331\e332\e237\*(Aq ;
\&
\&    my $ebcdic_string = $ascii_string;
\&    eval \*(Aq$ebcdic_string =~ tr/\*(Aq . $cp_037 . \*(Aq/\e000\-\e377/\*(Aq;
.Ve
.PP
To convert from \s-1EBCDIC\s0 037 to \s-1ASCII\s0 just reverse the order of the tr/// 
arguments like so:
.PP
.Vb 2
\&    my $ascii_string = $ebcdic_string;
\&    eval \*(Aq$ascii_string =~ tr/\e000\-\e377/\*(Aq . $cp_037 . \*(Aq/\*(Aq;
.Ve
.PP
Similarly one could take the output of the third column from recipe 0 to
obtain a \f(CW$cp_1047\fR table.  The fourth column of the output from recipe
0 could provide a \f(CW$cp_posix_bc\fR table suitable for transcoding as well.
.Sh "iconv"
.IX Subsection "iconv"
\&\s-1XPG\s0 operability often implies the presence of an \fIiconv\fR utility
available from the shell or from the C library.  Consult your system's
documentation for information on iconv.
.PP
On \s-1OS/390\s0 or z/OS see the \fIiconv\fR\|(1) manpage.  One way to invoke the iconv 
shell utility from within perl would be to:
.PP
.Vb 2
\&    # OS/390 or z/OS example
\&    $ascii_data = \`echo \*(Aq$ebcdic_data\*(Aq| iconv \-f IBM\-1047 \-t ISO8859\-1\`
.Ve
.PP
or the inverse map:
.PP
.Vb 2
\&    # OS/390 or z/OS example
\&    $ebcdic_data = \`echo \*(Aq$ascii_data\*(Aq| iconv \-f ISO8859\-1 \-t IBM\-1047\`
.Ve
.PP
For other perl based conversion options see the Convert::* modules on \s-1CPAN\s0.
.Sh "C \s-1RTL\s0"
.IX Subsection "C RTL"
The \s-1OS/390\s0 and z/OS C run time libraries provide \fI_atoe()\fR and \fI_etoa()\fR functions.
.SH "OPERATOR DIFFERENCES"
.IX Header "OPERATOR DIFFERENCES"
The \f(CW\*(C`..\*(C'\fR range operator treats certain character ranges with 
care on \s-1EBCDIC\s0 machines.  For example the following array
will have twenty six elements on either an \s-1EBCDIC\s0 machine
or an \s-1ASCII\s0 machine:
.PP
.Vb 1
\&    @alphabet = (\*(AqA\*(Aq..\*(AqZ\*(Aq);   #  $#alphabet == 25
.Ve
.PP
The bitwise operators such as & ^ | may return different results
when operating on string or character data in a perl program running 
on an \s-1EBCDIC\s0 machine than when run on an \s-1ASCII\s0 machine.  Here is
an example adapted from the one in perlop:
.PP
.Vb 5
\&    # EBCDIC\-based examples
\&    print "j p \en" ^ " a h";                      # prints "JAPH\en"
\&    print "JA" | "  ph\en";                        # prints "japh\en" 
\&    print "JAPH\enJunk" & "\e277\e277\e277\e277\e277";  # prints "japh\en";
\&    print \*(Aqp N$\*(Aq ^ " E<H\en";                      # prints "Perl\en";
.Ve
.PP
An interesting property of the 32 C0 control characters
in the \s-1ASCII\s0 table is that they can \*(L"literally\*(R" be constructed
as control characters in perl, e.g. \f(CW\*(C`(chr(0) eq "\ec@")\*(C'\fR 
\&\f(CW\*(C`(chr(1) eq "\ecA")\*(C'\fR, and so on.  Perl on \s-1EBCDIC\s0 machines has been 
ported to take \*(L"\ec@\*(R" to \fIchr\fR\|(0) and \*(L"\ecA\*(R" to \fIchr\fR\|(1) as well, but the
thirty three characters that result depend on which code page you are
using.  The table below uses the character names from the previous table 
but with substitutions such as s/START \s-1OF/S\s0.O./; s/END \s-1OF\s0 /E.O./; 
s/TRANSMISSION/TRANS./; s/TABULATION/TAB./; s/VERTICAL/VERT./; 
s/HORIZONTAL/HORIZ./; s/DEVICE \s-1CONTROL/D\s0.C./; s/SEPARATOR/SEP./; 
s/NEGATIVE \s-1ACKNOWLEDGE/NEG\s0. \s-1ACK\s0./;.  The POSIX-BC and 1047 sets are
identical throughout this range and differ from the 0037 set at only 
one spot (21 decimal).  Note that the \f(CW\*(C`LINE FEED\*(C'\fR character
may be generated by \*(L"\ecJ\*(R" on \s-1ASCII\s0 machines but by \*(L"\ecU\*(R" on 1047 or POSIX-BC 
machines and cannot be generated as a \f(CW"\ec.letter."\fR control character on 
0037 machines.  Note also that \*(L"\ec\e\e\*(R" maps to two characters
not one.
.PP
.Vb 10
\&    chr   ord  8859\-1               0037                1047 && POSIX\-BC     
\&    \-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-
\&    "\ec?" 127  <DELETE>             "                   "              ***><
\&    "\ec@"   0  <NULL>               <NULL>              <NULL>         ***><
\&    "\ecA"   1  <S.O. HEADING>       <S.O. HEADING>      <S.O. HEADING> 
\&    "\ecB"   2  <S.O. TEXT>          <S.O. TEXT>         <S.O. TEXT>
\&    "\ecC"   3  <E.O. TEXT>          <E.O. TEXT>         <E.O. TEXT>
\&    "\ecD"   4  <E.O. TRANS.>        <C1 28>             <C1 28> 
\&    "\ecE"   5  <ENQUIRY>            <HORIZ. TAB.>       <HORIZ. TAB.>    
\&    "\ecF"   6  <ACKNOWLEDGE>        <C1 6>              <C1 6>   
\&    "\ecG"   7  <BELL>               <DELETE>            <DELETE>   
\&    "\ecH"   8  <BACKSPACE>          <C1 23>             <C1 23>
\&    "\ecI"   9  <HORIZ. TAB.>        <C1 13>             <C1 13>
\&    "\ecJ"  10  <LINE FEED>          <C1 14>             <C1 14>
\&    "\ecK"  11  <VERT. TAB.>         <VERT. TAB.>        <VERT. TAB.>
\&    "\ecL"  12  <FORM FEED>          <FORM FEED>         <FORM FEED>    
\&    "\ecM"  13  <CARRIAGE RETURN>    <CARRIAGE RETURN>   <CARRIAGE RETURN> 
\&    "\ecN"  14  <SHIFT OUT>          <SHIFT OUT>         <SHIFT OUT>
\&    "\ecO"  15  <SHIFT IN>           <SHIFT IN>          <SHIFT IN>
\&    "\ecP"  16  <DATA LINK ESCAPE>   <DATA LINK ESCAPE>  <DATA LINK ESCAPE> 
\&    "\ecQ"  17  <D.C. ONE>           <D.C. ONE>          <D.C. ONE>
\&    "\ecR"  18  <D.C. TWO>           <D.C. TWO>          <D.C. TWO>
\&    "\ecS"  19  <D.C. THREE>         <D.C. THREE>        <D.C. THREE> 
\&    "\ecT"  20  <D.C. FOUR>          <C1 29>             <C1 29> 
\&    "\ecU"  21  <NEG. ACK.>          <C1 5>              <LINE FEED>    ***
\&    "\ecV"  22  <SYNCHRONOUS IDLE>   <BACKSPACE>         <BACKSPACE>
\&    "\ecW"  23  <E.O. TRANS. BLOCK>  <C1 7>              <C1 7>
\&    "\ecX"  24  <CANCEL>             <CANCEL>            <CANCEL>
\&    "\ecY"  25  <E.O. MEDIUM>        <E.O. MEDIUM>       <E.O. MEDIUM>
\&    "\ecZ"  26  <SUBSTITUTE>         <C1 18>             <C1 18>
\&    "\ec["  27  <ESCAPE>             <C1 15>             <C1 15>
\&    "\ec\e\e" 28  <FILE SEP.>\e         <FILE SEP.>\e        <FILE SEP.>\e
\&    "\ec]"  29  <GROUP SEP.>         <GROUP SEP.>        <GROUP SEP.>
\&    "\ec^"  30  <RECORD SEP.>        <RECORD SEP.>       <RECORD SEP.>  ***><
\&    "\ec_"  31  <UNIT SEP.>          <UNIT SEP.>         <UNIT SEP.>    ***><
.Ve
.SH "FUNCTION DIFFERENCES"
.IX Header "FUNCTION DIFFERENCES"
.IP "\fIchr()\fR" 8
.IX Item "chr()"
\&\fIchr()\fR must be given an \s-1EBCDIC\s0 code number argument to yield a desired 
character return value on an \s-1EBCDIC\s0 machine.  For example:
.Sp
.Vb 1
\&    $CAPITAL_LETTER_A = chr(193);
.Ve
.IP "\fIord()\fR" 8
.IX Item "ord()"
\&\fIord()\fR will return \s-1EBCDIC\s0 code number values on an \s-1EBCDIC\s0 machine.
For example:
.Sp
.Vb 1
\&    $the_number_193 = ord("A");
.Ve
.IP "\fIpack()\fR" 8
.IX Item "pack()"
The c and C templates for \fIpack()\fR are dependent upon character set 
encoding.  Examples of usage on \s-1EBCDIC\s0 include:
.Sp
.Vb 4
\&    $foo = pack("CCCC",193,194,195,196);
\&    # $foo eq "ABCD"
\&    $foo = pack("C4",193,194,195,196);
\&    # same thing
\&
\&    $foo = pack("ccxxcc",193,194,195,196);
\&    # $foo eq "AB\e0\e0CD"
.Ve
.IP "\fIprint()\fR" 8
.IX Item "print()"
One must be careful with scalars and strings that are passed to
print that contain \s-1ASCII\s0 encodings.  One common place
for this to occur is in the output of the \s-1MIME\s0 type header for
\&\s-1CGI\s0 script writing.  For example, many perl programming guides 
recommend something similar to:
.Sp
.Vb 2
\&    print "Content\-type:\ettext/html\e015\e012\e015\e012"; 
\&    # this may be wrong on EBCDIC
.Ve
.Sp
Under the \s-1IBM\s0 \s-1OS/390\s0 \s-1USS\s0 Web Server or WebSphere on z/OS for example 
you should instead write that as:
.Sp
.Vb 1
\&    print "Content\-type:\ettext/html\er\en\er\en"; # OK for DGW et alia
.Ve
.Sp
That is because the translation from \s-1EBCDIC\s0 to \s-1ASCII\s0 is done
by the web server in this case (such code will not be appropriate for
the Macintosh however).  Consult your web server's documentation for 
further details.
.IP "\fIprintf()\fR" 8
.IX Item "printf()"
The formats that can convert characters to numbers and vice versa
will be different from their \s-1ASCII\s0 counterparts when executed
on an \s-1EBCDIC\s0 machine.  Examples include:
.Sp
.Vb 1
\&    printf("%c%c%c",193,194,195);  # prints ABC
.Ve
.IP "\fIsort()\fR" 8
.IX Item "sort()"
\&\s-1EBCDIC\s0 sort results may differ from \s-1ASCII\s0 sort results especially for 
mixed case strings.  This is discussed in more detail below.
.IP "\fIsprintf()\fR" 8
.IX Item "sprintf()"
See the discussion of \fIprintf()\fR above.  An example of the use
of sprintf would be:
.Sp
.Vb 1
\&    $CAPITAL_LETTER_A = sprintf("%c",193);
.Ve
.IP "\fIunpack()\fR" 8
.IX Item "unpack()"
See the discussion of \fIpack()\fR above.
.SH "REGULAR EXPRESSION DIFFERENCES"