NAME

       option - Add/retrieve window options to/from the option database

SYNOPSIS

       option add pattern value ?priority?
       option clear
       option get window name class
       option readfile fileName ?priority?
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DESCRIPTION

       The  option  command  allows you to add entries to the Tk option database or to retrieve options from the
       database.  The add form of the command adds a new option to the database.  Pattern  contains  the  option
       being  specified,  and  consists  of  names and/or classes separated by asterisks or dots, in the usual X
       format (see PATTERN FORMAT).  Value contains a text string to associate with pattern;  this is the  value
       that  will be returned in calls to Tk_GetOption or by invocations of the option get command.  If priority
       is specified, it indicates the priority level for this option (see below for legal values);  it  defaults
       to interactive.  This command always returns an empty string.

       The option clear command clears the option database.  Default options (from the RESOURCE_MANAGER property
       or  the  .Xdefaults file) will be reloaded automatically the next time an option is added to the database
       or removed from it.  This command always returns an empty string.

       The option get command returns the value of the option specified for window under  name  and  class.   If
       several  entries in the option database match window, name, and class, then the command returns whichever
       was created with highest priority level.  If there are several matching  entries  at  the  same  priority
       level,  then it returns whichever entry was most recently entered into the option database.  If there are
       no matching entries, then the empty string is returned.

       The readfile form of the command reads fileName, which should have the standard format for an X  resource
       database  such as .Xdefaults, and adds all the options specified in that file to the option database.  If
       priority is specified, it indicates the priority level at which to enter the options;  priority  defaults
       to interactive.

       The file is read through a channel which is in "utf-8" encoding, invalid byte sequences are automatically
       converted  to valid ones.  This means that encodings like ISO 8859-1 or cp1252 with high probability will
       work as well, but this cannot be guaranteed.  This cannot be changed, setting the [encoding  system]  has
       no effect.

       The  priority  arguments  to  the  option  command  are  normally specified symbolically using one of the
       following values:

       widgetDefault
              Level 20.  Used for default values hard-coded into widgets.

       startupFile
              Level 40.  Used for options specified in application-specific startup files.

       userDefault
              Level 60.  Used for options  specified  in  user-specific  defaults  files,  such  as  .Xdefaults,
              resource databases loaded into the X server, or user-specific startup files.

       interactive
              Level  80.   Used  for  options  specified interactively after the application starts running.  If
              priority is not specified, it defaults to this level.

       Any of the above keywords may be abbreviated.  In addition, priorities may be specified numerically using
       integers between 0 and 100, inclusive.  The numeric form is probably a bad idea except for  new  priority
       levels other than the ones given above.

PATTERN FORMAT

       Patterns  consist of a sequence of words separated by either periods, “.”, or asterisks “*”.  The overall
       pattern may also be optionally preceded by an asterisk.

       Each word in the pattern conventionally starts with either an upper-case letter (in which case it denotes
       the class of either a widget or an option) or any other character, when it denotes the name of  a  widget
       or  option.  The last word in the pattern always indicates the option; the preceding ones constrain which
       widgets that option will be looked for in.

       When two words are separated by a period, the latter widget must be a direct child of the former (or  the
       option must apply to only the indicated widgets).  When two words are separated by an asterisk, any depth
       of  widgets may lie between the former and latter widgets (and the option applies to all widgets that are
       children of the former widget).

       If the overall pattern is preceded by an asterisk, then the  overall  pattern  applies  anywhere  it  can
       throughout  the  whole  widget  hierarchy. Otherwise the first word of the pattern is matched against the
       name and class of the “.”  toplevel, which are usually set by options to wish.

EXAMPLES

       Instruct every button in the application to have red text on it unless explicitly overridden, by  setting
       the foreground for the Button class (note that on some platforms the option is ignored):
              option add *Button.foreground red startupFile

       Allow  users  to  control  what happens in an entry widget when the Return key is pressed by specifying a
       script in the option database and add a default option for that which rings the bell:
              entry .e
              bind .e <Return> [option get .e returnCommand Command]
              option add *.e.returnCommand bell widgetDefault

SEE ALSO

       options(3tk), wish(1)

KEYWORDS

       database, option, priority, retrieve

Tk                                                                                                   option(3tk)