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encoding(n)                                 Tcl Built-In Commands                                encoding(n)



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NAME
       encoding - Manipulate encodings

SYNOPSIS
       encoding option ?arg arg ...?
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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 characters 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 encoding.  If encoding is not speci-fied, specified,
              fied, 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 charac-ter. character.
              ter.  If encoding is not specified, the current system encoding is used.

       encoding dirs ?directoryList?
              Tcl can load encoding data files from the file system that describe additional  encodings  for |
              it  to  work with. This command sets the search path for *.enc encoding data files to the list |
              of directories directoryList. If directoryList is omitted then the command returns the current |
              list of directories that make up the search path. It is an error for directoryList to not be a |
              valid list. If, when a search for an encoding data file is happening, an element  in  directo- |
              ryList does not refer to a readable, searchable directory, that element is ignored.

       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 cur-rent current
              rent 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.  However, 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)