encoding(n)

______________________________________________________________________________

NAME

       encoding - Manipulate encodings

SYNOPSIS

       encoding option ?arg arg ...?
_________________________________________________________________

INTRODUCTION

       Strings  in Tcl are encoded using 16-bit Unicode characters.  Different
       operating system interfaces or applications  may  generate  strings  in
       other  encodings  such  as  Shift-JIS.   The  encoding command helps to
       bridge the gap between Unicode and these other formats.

DESCRIPTION

       Performs one of  several  encoding  related  operations,  depending  on
       option.  The legal options are:

       encoding convertfrom ?encoding? data
              Convert  data to Unicode from the specified encoding.  The char-
              acters in data are treated as binary data where the lower 8-bits
              of  each  character  is  taken  as a single byte.  The resulting
              sequence of bytes is treated as a string in the specified encod-
              ing.   If encoding is not specified, the current system encoding
              is used.

       encoding convertto ?encoding? string
              Convert string from Unicode  to  the  specified  encoding.   The
              result  is  a  sequence  of  bytes that represents the converted
              string.  Each byte is stored in the lower 8-bits  of  a  Unicode
              character.   If  encoding  is  not specified, the current system
              encoding is used.

       encoding names
              Returns a list containing the names of all of the encodings that
              are currently available.

       encoding system ?encoding?
              Set the system encoding to encoding. If encoding is omitted then
              the command returns the current  system  encoding.   The  system
              encoding is used whenever Tcl passes strings to system calls.

EXAMPLE

       It  is  common  practice to write script files using a text editor that
       produces output in the euc-jp  encoding,  which  represents  the  ASCII
       characters  as  singe bytes and Japanese characters as two bytes.  This
       makes it easy to embed literal strings  that  correspond  to  non-ASCII
       characters  by  simply typing the strings in place in the script.  How-
       ever, because the source command always reads files using  the  current
       system  encoding,  Tcl  will  only source such files correctly when the
       encoding used to write the file is the same.  This tends not to be true
       in  an  internationalized  setting.   For  example,  if such a file was
       sourced in North America (where the ISO8859-1 is normally  used),  each
       byte  in the file would be treated as a separate character that maps to
       the 00 page in Unicode.  The resulting Tcl strings will not contain the
       expected Japanese characters.  Instead, they will contain a sequence of
       Latin-1 characters that correspond to the bytes of the original string.
       The encoding command can be used to convert this string to the expected
       Japanese Unicode characters.  For example,
              set s [encoding convertfrom euc-jp "\xA4\xCF"]
       would return the Unicode string "\u306F", which is the Hiragana  letter
       HA.

SEE ALSO

       Tcl_GetEncoding(3)

KEYWORDS

       encoding

Tcl                                   8.1                          encoding(n)