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