Provided by: rxvt-unicode_9.19-1_amd64 bug

NAME

       urxvtperl - rxvt-unicode's embedded perl interpreter

SYNOPSIS

          # create a file grab_test in $HOME:

          sub on_sel_grab {
             warn "you selected ", $_[0]->selection;
             ()
          }

          # start a urxvt using it:

          urxvt --perl-lib $HOME -pe grab_test

DESCRIPTION

       Every time a terminal object gets created, extension scripts specified via the "perl" resource are loaded
       and associated with it.

       Scripts are compiled in a 'use strict "vars"' and 'use utf8' environment, and thus must be encoded as
       UTF-8.

       Each script will only ever be loaded once, even in urxvtd, where scripts will be shared (but not enabled)
       for all terminals.

       You can disable the embedded perl interpreter by setting both "perl-ext" and "perl-ext-common" resources
       to the empty string.

PREPACKAGED EXTENSIONS

       A number of extensions are delivered with this release. You can find them in <libdir>/urxvt/perl/, and
       the documentation can be viewed using man urxvt-<EXTENSIONNAME>.

       You can activate them like this:

         urxvt -pe <extensionname>

       Or by adding them to the resource for extensions loaded by default:

         URxvt.perl-ext-common: default,selection-autotransform

       Extensions that add command line parameters or resources on their own are loaded automatically when used.

API DOCUMENTATION

   General API Considerations
       All objects (such as terminals, time watchers etc.) are typical reference-to-hash objects. The hash can
       be used to store anything you like. All members starting with an underscore (such as "_ptr" or "_hook")
       are reserved for internal uses and MUST NOT be accessed or modified).

       When objects are destroyed on the C++ side, the perl object hashes are emptied, so its best to store
       related objects such as time watchers and the like inside the terminal object so they get destroyed as
       soon as the terminal is destroyed.

       Argument names also often indicate the type of a parameter. Here are some hints on what they mean:

       $text
           Rxvt-unicode's special way of encoding text, where one "unicode" character always represents one
           screen cell. See ROW_t for a discussion of this format.

       $string
           A perl text string, with an emphasis on text. It can store all unicode characters and is to be
           distinguished with text encoded in a specific encoding (often locale-specific) and binary data.

       $octets
           Either binary data or - more common - a text string encoded in a locale-specific way.

       $keysym
           an integer that is a valid X11 keysym code. You can convert a string into a keysym and viceversa by
           using "XStringToKeysym" and "XKeysymToString".

   Extension Objects
       Every perl extension is a perl class. A separate perl object is created for each terminal, and each
       terminal has its own set of extension objects, which are passed as the first parameter to hooks. So
       extensions can use their $self object without having to think about clashes with other extensions or
       other terminals, with the exception of methods and members that begin with an underscore character "_":
       these are reserved for internal use.

       Although it isn't a "urxvt::term" object, you can call all methods of the "urxvt::term" class on this
       object.

       Additional methods only supported for extension objects are described in the "urxvt::extension" section
       below.

   Hooks
       The following subroutines can be declared in extension files, and will be called whenever the relevant
       event happens.

       The first argument passed to them is an extension object as described in the in the "Extension Objects"
       section.

       All of these hooks must return a boolean value. If any of the called hooks returns true, then the event
       counts as being consumed, and the relevant action might not be carried out by the C++ code.

       When in doubt, return a false value (preferably "()").

       on_init $term
           Called after a new terminal object has been initialized, but before windows are created or the
           command gets run. Most methods are unsafe to call or deliver senseless data, as terminal size and
           other characteristics have not yet been determined. You can safely query and change resources and
           options, though. For many purposes the "on_start" hook is a better place.

       on_start $term
           Called at the very end of initialisation of a new terminal, just before trying to map (display) the
           toplevel and returning to the main loop.

       on_destroy $term
           Called whenever something tries to destroy terminal, when the terminal is still fully functional (not
           for long, though).

       on_reset $term
           Called after the screen is "reset" for any reason, such as resizing or control sequences. Here is
           where you can react on changes to size-related variables.

       on_child_start $term, $pid
           Called just after the child process has been "fork"ed.

       on_child_exit $term, $status
           Called just after the child process has exited. $status is the status from "waitpid".

       on_sel_make $term, $eventtime
           Called whenever a selection has been made by the user, but before the selection text is copied, so
           changes to the beginning, end or type of the selection will be honored.

           Returning a true value aborts selection making by urxvt, in which case you have to make a selection
           yourself by calling "$term->selection_grab".

       on_sel_grab $term, $eventtime
           Called whenever a selection has been copied, but before the selection is requested from the server.
           The selection text can be queried and changed by calling "$term->selection".

           Returning a true value aborts selection grabbing. It will still be highlighted.

       on_sel_extend $term
           Called whenever the user tries to extend the selection (e.g. with a double click) and is either
           supposed to return false (normal operation), or should extend the selection itself and return true to
           suppress the built-in processing. This can happen multiple times, as long as the callback returns
           true, it will be called on every further click by the user and is supposed to enlarge the selection
           more and more, if possible.

           See the selection example extension.

       on_view_change $term, $offset
           Called whenever the view offset changes, i.e. the user or program scrolls. Offset 0 means display the
           normal terminal, positive values show this many lines of scrollback.

       on_scroll_back $term, $lines, $saved
           Called whenever lines scroll out of the terminal area into the scrollback buffer. $lines is the
           number of lines scrolled out and may be larger than the scroll back buffer or the terminal.

           It is called before lines are scrolled out (so rows 0 .. min ($lines - 1, $nrow - 1) represent the
           lines to be scrolled out). $saved is the total number of lines that will be in the scrollback buffer.

       on_osc_seq $term, $op, $args, $resp
           Called on every OSC sequence and can be used to suppress it or modify its behaviour. The default
           should be to return an empty list. A true value suppresses execution of the request completely. Make
           sure you don't get confused by recursive invocations when you output an OSC sequence within this
           callback.

           "on_osc_seq_perl" should be used for new behaviour.

       on_osc_seq_perl $term, $args, $resp
           Called whenever the ESC ] 777 ; string ST command sequence (OSC = operating system command) is
           processed. Cursor position and other state information is up-to-date when this happens. For
           interoperability, the string should start with the extension name (sans -osc) and a semicolon, to
           distinguish it from commands for other extensions, and this might be enforced in the future.

           For example, "overlay-osc" uses this:

              sub on_osc_seq_perl {
                 my ($self, $osc, $resp) = @_;

                 return unless $osc =~ s/^overlay;//;

                 ... process remaining $osc string
              }

           Be careful not ever to trust (in a security sense) the data you receive, as its source can not easily
           be controlled (e-mail content, messages from other users on the same system etc.).

           For responses, $resp contains the end-of-args separator used by the sender.

       on_add_lines $term, $string
           Called whenever text is about to be output, with the text as argument. You can filter/change and
           output the text yourself by returning a true value and calling "$term->scr_add_lines" yourself.
           Please note that this might be very slow, however, as your hook is called for all text being output.

       on_tt_write $term, $octets
           Called whenever some data is written to the tty/pty and can be used to suppress or filter tty input.

       on_tt_paste $term, $octets
           Called whenever text is about to be pasted, with the text as argument. You can filter/change and
           paste the text yourself by returning a true value and calling "$term->tt_paste" yourself. $octets is
           locale-encoded.

       on_line_update $term, $row
           Called whenever a line was updated or changed. Can be used to filter screen output (e.g. underline
           urls or other useless stuff). Only lines that are being shown will be filtered, and, due to
           performance reasons, not always immediately.

           The row number is always the topmost row of the line if the line spans multiple rows.

           Please note that, if you change the line, then the hook might get called later with the already-
           modified line (e.g. if unrelated parts change), so you cannot just toggle rendition bits, but only
           set them.

       on_refresh_begin $term
           Called just before the screen gets redrawn. Can be used for overlay or similar effects by modifying
           the terminal contents in refresh_begin, and restoring them in refresh_end. The built-in overlay and
           selection display code is run after this hook, and takes precedence.

       on_refresh_end $term
           Called just after the screen gets redrawn. See "on_refresh_begin".

       on_user_command $term, $string
           Called whenever a user-configured event is being activated (e.g. via a "perl:string" action bound to
           a key, see description of the keysym resource in the urxvt(1) manpage).

           The event is simply the action string. This interface is assumed to change slightly in the future.

       on_register_command $term, $keysym, $modifiermask, $string
           Called after parsing a keysym resource but before registering the associated binding. If this hook
           returns TRUE the binding is not registered. It can be used to modify a binding by calling
           "register_command".

       on_resize_all_windows $term, $new_width, $new_height
           Called just after the new window size has been calculated, but before windows are actually being
           resized or hints are being set. If this hook returns TRUE, setting of the window hints is being
           skipped.

       on_x_event $term, $event
           Called on every X event received on the vt window (and possibly other windows). Should only be used
           as a last resort. Most event structure members are not passed.

       on_root_event $term, $event
           Like "on_x_event", but is called for events on the root window.

       on_focus_in $term
           Called whenever the window gets the keyboard focus, before rxvt-unicode does focus in processing.

       on_focus_out $term
           Called whenever the window loses keyboard focus, before rxvt-unicode does focus out processing.

       on_configure_notify $term, $event
       on_property_notify $term, $event
       on_key_press $term, $event, $keysym, $octets
       on_key_release $term, $event, $keysym
       on_button_press $term, $event
       on_button_release $term, $event
       on_motion_notify $term, $event
       on_map_notify $term, $event
       on_unmap_notify $term, $event
           Called whenever the corresponding X event is received for the terminal. If the hook returns true,
           then the event will be ignored by rxvt-unicode.

           The event is a hash with most values as named by Xlib (see the XEvent manpage), with the additional
           members "row" and "col", which are the (real, not screen-based) row and column under the mouse
           cursor.

           "on_key_press" additionally receives the string rxvt-unicode would output, if any, in locale-specific
           encoding.

           subwindow.

       on_client_message $term, $event
       on_wm_protocols $term, $event
       on_wm_delete_window $term, $event
           Called when various types of ClientMessage events are received (all with format=32, WM_PROTOCOLS or
           WM_PROTOCOLS:WM_DELETE_WINDOW).

       on_bell $term
           Called on receipt of a bell character.

   Variables in the "urxvt" Package
       $urxvt::LIBDIR
           The rxvt-unicode library directory, where, among other things, the perl modules and scripts are
           stored.

       $urxvt::RESCLASS, $urxvt::RESCLASS
           The resource class and name rxvt-unicode uses to look up X resources.

       $urxvt::RXVTNAME
           The basename of the installed binaries, usually "urxvt".

       $urxvt::TERM
           The current terminal. This variable stores the current "urxvt::term" object, whenever a callback/hook
           is executing.

       @urxvt::TERM_INIT
           All code references in this array will be called as methods of the next newly created "urxvt::term"
           object (during the "on_init" phase). The array gets cleared before the code references that were in
           it are being executed, so references can push themselves onto it again if they so desire.

           This complements to the perl-eval command line option, but gets executed first.

       @urxvt::TERM_EXT
           Works similar to @TERM_INIT, but contains perl package/class names, which get registered as normal
           extensions after calling the hooks in @TERM_INIT but before other extensions. Gets cleared just like
           @TERM_INIT.

   Functions in the "urxvt" Package
       urxvt::fatal $errormessage
           Fatally aborts execution with the given error message (which should include a trailing newline).
           Avoid at all costs! The only time this is acceptable (and useful) is in the init hook, where it
           prevents the terminal from starting up.

       urxvt::warn $string
           Calls "rxvt_warn" with the given string which should include a trailing newline. The module also
           overwrites the "warn" builtin with a function that calls this function.

           Using this function has the advantage that its output ends up in the correct place, e.g. on stderr of
           the connecting urxvtc client.

           Messages have a size limit of 1023 bytes currently.

       @terms = urxvt::termlist
           Returns all urxvt::term objects that exist in this process, regardless of whether they are started,
           being destroyed etc., so be careful. Only term objects that have perl extensions attached will be
           returned (because there is no urxvt::term object associated with others).

       $time = urxvt::NOW
           Returns the "current time" (as per the event loop).

       urxvt::CurrentTime
       urxvt::ShiftMask, LockMask, ControlMask, Mod1Mask, Mod2Mask, Mod3Mask, Mod4Mask, Mod5Mask, Button1Mask,
       Button2Mask, Button3Mask, Button4Mask, Button5Mask, AnyModifier
       urxvt::NoEventMask, KeyPressMask, KeyReleaseMask, ButtonPressMask, ButtonReleaseMask, EnterWindowMask,
       LeaveWindowMask, PointerMotionMask, PointerMotionHintMask, Button1MotionMask, Button2MotionMask,
       Button3MotionMask, Button4MotionMask, Button5MotionMask, ButtonMotionMask, KeymapStateMask, ExposureMask,
       VisibilityChangeMask, StructureNotifyMask, ResizeRedirectMask, SubstructureNotifyMask,
       SubstructureRedirectMask, FocusChangeMask, PropertyChangeMask, ColormapChangeMask, OwnerGrabButtonMask
       urxvt::KeyPress, KeyRelease, ButtonPress, ButtonRelease, MotionNotify, EnterNotify, LeaveNotify, FocusIn,
       FocusOut, KeymapNotify, Expose, GraphicsExpose, NoExpose, VisibilityNotify, CreateNotify, DestroyNotify,
       UnmapNotify, MapNotify, MapRequest, ReparentNotify, ConfigureNotify, ConfigureRequest, GravityNotify,
       ResizeRequest, CirculateNotify, CirculateRequest, PropertyNotify, SelectionClear, SelectionRequest,
       SelectionNotify, ColormapNotify, ClientMessage, MappingNotify
           Various constants for use in X calls and event processing.

   RENDITION
       Rendition bitsets contain information about colour, font, font styles and similar information for each
       screen cell.

       The following "macros" deal with changes in rendition sets. You should never just create a bitset, you
       should always modify an existing one, as they contain important information required for correct
       operation of rxvt-unicode.

       $rend = urxvt::DEFAULT_RSTYLE
           Returns the default rendition, as used when the terminal is starting up or being reset. Useful as a
           base to start when creating renditions.

       $rend = urxvt::OVERLAY_RSTYLE
           Return the rendition mask used for overlays by default.

       $rendbit = urxvt::RS_Bold, urxvt::RS_Italic, urxvt::RS_Blink, urxvt::RS_RVid, urxvt::RS_Uline
           Return the bit that enabled bold, italic, blink, reverse-video and underline, respectively. To enable
           such a style, just logically OR it into the bitset.

       $foreground = urxvt::GET_BASEFG $rend
       $background = urxvt::GET_BASEBG $rend
           Return the foreground/background colour index, respectively.

       $rend = urxvt::SET_FGCOLOR $rend, $new_colour
       $rend = urxvt::SET_BGCOLOR $rend, $new_colour
       $rend = urxvt::SET_COLOR $rend, $new_fg, $new_bg
           Replace the foreground/background colour in the rendition mask with the specified one.

       $value = urxvt::GET_CUSTOM $rend
           Return the "custom" value: Every rendition has 5 bits for use by extensions. They can be set and
           changed as you like and are initially zero.

       $rend = urxvt::SET_CUSTOM $rend, $new_value
           Change the custom value.

   The "urxvt::term::extension" class
       Each extension attached to a terminal object is represented by a "urxvt::term::extension" object.

       You can use these objects, which are passed to all callbacks to store any state related to the terminal
       and extension instance.

       The methods (And data members) documented below can be called on extension objects, in addition to call
       methods documented for the <urxvt::term> class.

       $urxvt_term = $self->{term}
           Returns the "urxvt::term" object associated with this instance of the extension. This member must not
           be changed in any way.

       $self->enable ($hook_name => $cb[, $hook_name => $cb..])
           Dynamically enable the given hooks (named without the "on_" prefix) for this extension, replacing any
           previous hook. This is useful when you want to overwrite time-critical hooks only temporarily.

           To install additional callbacks for the same hook, you can use the "on" method of the "urxvt::term"
           class.

       $self->disable ($hook_name[, $hook_name..])
           Dynamically disable the given hooks.

       $guard = $self->on ($hook_name => $cb[, $hook_name => $cb..])
           Similar to the "enable" enable, but installs additional callbacks for the given hook(s) (that is, it
           doesn't replace existing callbacks), and returns a guard object. When the guard object is destroyed
           the callbacks are disabled again.

       $self->x_resource ($pattern)
       $self->x_resource_boolean ($pattern)
           These methods support an additional "%" prefix when called on an extension object - see the
           description of these methods in the "urxvt::term" class for details.

   The "urxvt::anyevent" Class
       The sole purpose of this class is to deliver an interface to the "AnyEvent" module - any module using it
       will work inside urxvt without further programming. The only exception is that you cannot wait on
       condition variables, but non-blocking condvar use is ok.

       In practical terms this means is that you cannot use blocking APIs, but the non-blocking variant should
       work.

   The "urxvt::term" Class
       $term = new urxvt::term $envhashref, $rxvtname, [arg...]
           Creates a new terminal, very similar as if you had started it with system "$rxvtname, arg...".
           $envhashref must be a reference to a %ENV-like hash which defines the environment of the new
           terminal.

           Croaks (and probably outputs an error message) if the new instance couldn't be created.  Returns
           "undef" if the new instance didn't initialise perl, and the terminal object otherwise. The "init" and
           "start" hooks will be called before this call returns, and are free to refer to global data (which is
           race free).

       $term->destroy
           Destroy the terminal object (close the window, free resources etc.). Please note that urxvt will not
           exit as long as any event watchers (timers, io watchers) are still active.

       $term->exec_async ($cmd[, @args])
           Works like the combination of the "fork"/"exec" builtins, which executes ("starts") programs in the
           background. This function takes care of setting the user environment before exec'ing the command
           (e.g. "PATH") and should be preferred over explicit calls to "exec" or "system".

           Returns the pid of the subprocess or "undef" on error.

       $isset = $term->option ($optval[, $set])
           Returns true if the option specified by $optval is enabled, and optionally change it. All option
           values are stored by name in the hash %urxvt::OPTION. Options not enabled in this binary are not in
           the hash.

           Here is a likely non-exhaustive list of option names, please see the source file /src/optinc.h to see
           the actual list:

            borderLess buffered console cursorBlink cursorUnderline hold iconic
            insecure intensityStyles iso14755 iso14755_52 jumpScroll loginShell
            mapAlert meta8 mouseWheelScrollPage override_redirect pastableTabs
            pointerBlank reverseVideo scrollBar scrollBar_floating scrollBar_right
            scrollTtyKeypress scrollTtyOutput scrollWithBuffer secondaryScreen
            secondaryScroll skipBuiltinGlyphs skipScroll transparent tripleclickwords
            urgentOnBell utmpInhibit visualBell

       $value = $term->resource ($name[, $newval])
           Returns the current resource value associated with a given name and optionally sets a new value.
           Setting values is most useful in the "init" hook. Unset resources are returned and accepted as
           "undef".

           The new value must be properly encoded to a suitable character encoding before passing it to this
           method. Similarly, the returned value may need to be converted from the used encoding to text.

           Resource names are as defined in src/rsinc.h. Colours can be specified as resource names of the form
           "color+<index>", e.g. "color+5". (will likely change).

           Please note that resource strings will currently only be freed when the terminal is destroyed, so
           changing options frequently will eat memory.

           Here is a likely non-exhaustive list of resource names, not all of which are supported in every
           build, please see the source file /src/rsinc.h to see the actual list:

             answerbackstring backgroundPixmap backspace_key blurradius
             boldFont boldItalicFont borderLess buffered chdir color cursorBlink
             cursorUnderline cutchars delete_key depth display_name embed ext_bwidth
             fade font geometry hold iconName iconfile imFont imLocale inputMethod
             insecure int_bwidth intensityStyles iso14755 iso14755_52 italicFont
             jumpScroll letterSpace lineSpace loginShell mapAlert meta8 modifier
             mouseWheelScrollPage name override_redirect pastableTabs path perl_eval
             perl_ext_1 perl_ext_2 perl_lib pointerBlank pointerBlankDelay
             preeditType print_pipe pty_fd reverseVideo saveLines scrollBar
             scrollBar_align scrollBar_floating scrollBar_right scrollBar_thickness
             scrollTtyKeypress scrollTtyOutput scrollWithBuffer scrollstyle
             secondaryScreen secondaryScroll shade skipBuiltinGlyphs skipScroll
             term_name title transient_for transparent tripleclickwords urgentOnBell
             utmpInhibit visualBell

       $value = $term->x_resource ($pattern)
           Returns the X-Resource for the given pattern, excluding the program or class name, i.e.
           "$term->x_resource ("boldFont")" should return the same value as used by this instance of rxvt-
           unicode. Returns "undef" if no resource with that pattern exists.

           Extensions that define extra resource or command line arguments also need to call this method to
           access their values.

           If the method is called on an extension object (basically, from an extension), then the special
           prefix "%." will be replaced by the name of the extension and a dot, and the lone string "%" will be
           replaced by the extension name itself. This makes it possible to code extensions so you can rename
           them and get a new set of commandline switches and resources without having to change the actual
           code.

           This method should only be called during the "on_start" hook, as there is only one resource database
           per display, and later invocations might return the wrong resources.

       $value = $term->x_resource_boolean ($pattern)
           Like "x_resource", above, but interprets the string value as a boolean and returns 1 for true values,
           0 for false values and "undef" if the resource or option isn't specified.

           You should always use this method to parse boolean resources.

       $success = $term->parse_keysym ($key, $octets)
           Adds a key binding exactly as specified via a resource. See the "keysym" resource in the urxvt(1)
           manpage.

       $term->register_command ($keysym, $modifiermask, $string)
           Adds a key binding. This is a lower level api compared to "parse_keysym", as it expects a parsed key
           description, and can be used only inside either the "on_init" hook, to add a binding, or the
           "on_register_command" hook, to modify a parsed binding.

       $rend = $term->rstyle ([$new_rstyle])
           Return and optionally change the current rendition. Text that is output by the terminal application
           will use this style.

       ($row, $col) = $term->screen_cur ([$row, $col])
           Return the current coordinates of the text cursor position and optionally set it (which is usually
           bad as applications don't expect that).

       ($row, $col) = $term->selection_mark ([$row, $col])
       ($row, $col) = $term->selection_beg ([$row, $col])
       ($row, $col) = $term->selection_end ([$row, $col])
           Return the current values of the selection mark, begin or end positions.

           When arguments are given, then the selection coordinates are set to $row and $col, and the selection
           screen is set to the current screen.

       $screen = $term->selection_screen ([$screen])
           Returns the current selection screen, and then optionally sets it.

       $term->selection_make ($eventtime[, $rectangular])
           Tries to make a selection as set by "selection_beg" and "selection_end". If $rectangular is true
           (default: false), a rectangular selection will be made. This is the preferred function to make a
           selection.

       $success = $term->selection_grab ($eventtime[, $clipboard])
           Try to acquire ownership of the primary (clipboard if $clipboard is true) selection from the server.
           The corresponding text can be set with the next method. No visual feedback will be given. This
           function is mostly useful from within "on_sel_grab" hooks.

       $oldtext = $term->selection ([$newtext, $clipboard])
           Return the current selection (clipboard if $clipboard is true) text and optionally replace it by
           $newtext.

       $term->selection_clear ([$clipboard])
           Revoke ownership of the primary (clipboard if $clipboard is true) selection.

       $term->overlay_simple ($x, $y, $text)
           Create a simple multi-line overlay box. See the next method for details.

       $term->overlay ($x, $y, $width, $height[, $rstyle[, $border]])
           Create a new (empty) overlay at the given position with the given width/height. $rstyle defines the
           initial rendition style (default: "OVERLAY_RSTYLE").

           If $border is 2 (default), then a decorative border will be put around the box.

           If either $x or $y is negative, then this is counted from the right/bottom side, respectively.

           This method returns an urxvt::overlay object. The overlay will be visible as long as the perl object
           is referenced.

           The methods currently supported on "urxvt::overlay" objects are:

           $overlay->set ($x, $y, $text[, $rend])
               Similar to "$term->ROW_t" and "$term->ROW_r" in that it puts text in rxvt-unicode's special
               encoding and an array of rendition values at a specific position inside the overlay.

               If $rend is missing, then the rendition will not be changed.

           $overlay->hide
               If visible, hide the overlay, but do not destroy it.

           $overlay->show
               If hidden, display the overlay again.

       $popup = $term->popup ($event)
           Creates a new "urxvt::popup" object that implements a popup menu. The $event must be the event
           causing the menu to pop up (a button event, currently).

       $cellwidth = $term->strwidth ($string)
           Returns the number of screen-cells this string would need. Correctly accounts for wide and combining
           characters.

       $octets = $term->locale_encode ($string)
           Convert the given text string into the corresponding locale encoding.

       $string = $term->locale_decode ($octets)
           Convert the given locale-encoded octets into a perl string.

       $term->scr_xor_span ($beg_row, $beg_col, $end_row, $end_col[, $rstyle])
           XORs the rendition values in the given span with the provided value (default: "RS_RVid"), which MUST
           NOT contain font styles. Useful in refresh hooks to provide effects similar to the selection.

       $term->scr_xor_rect ($beg_row, $beg_col, $end_row, $end_col[, $rstyle1[, $rstyle2]])
           Similar to "scr_xor_span", but xors a rectangle instead. Trailing whitespace will additionally be
           xored with the $rstyle2, which defaults to "RS_RVid | RS_Uline", which removes reverse video again
           and underlines it instead. Both styles MUST NOT contain font styles.

       $term->scr_bell
           Ring the bell!

       $term->scr_add_lines ($string)
           Write the given text string to the screen, as if output by the application running inside the
           terminal. It may not contain command sequences (escape codes), but is free to use line feeds,
           carriage returns and tabs. The string is a normal text string, not in locale-dependent encoding.

           Normally its not a good idea to use this function, as programs might be confused by changes in cursor
           position or scrolling. Its useful inside a "on_add_lines" hook, though.

       $term->scr_change_screen ($screen)
           Switch to given screen - 0 primary, 1 secondary.

       $term->cmd_parse ($octets)
           Similar to "scr_add_lines", but the argument must be in the locale-specific encoding of the terminal
           and can contain command sequences (escape codes) that will be interpreted.

       $term->tt_write ($octets)
           Write the octets given in $octets to the tty (i.e. as program input). To pass characters instead of
           octets, you should convert your strings first to the locale-specific encoding using
           "$term->locale_encode".

       $term->tt_paste ($octets)
           Write the octets given in $octets to the tty as a paste, converting NL to CR and bracketing the data
           with control sequences if bracketed paste mode is set.

       $old_events = $term->pty_ev_events ([$new_events])
           Replaces the event mask of the pty watcher by the given event mask. Can be used to suppress input and
           output handling to the pty/tty. See the description of "urxvt::timer->events". Make sure to always
           restore the previous value.

       $fd = $term->pty_fd
           Returns the master file descriptor for the pty in use, or "-1" if no pty is used.

       $windowid = $term->parent
           Return the window id of the toplevel window.

       $windowid = $term->vt
           Return the window id of the terminal window.

       $term->vt_emask_add ($x_event_mask)
           Adds the specified events to the vt event mask. Useful e.g. when you want to receive pointer events
           all the times:

              $term->vt_emask_add (urxvt::PointerMotionMask);

       $term->set_urgency ($set)
           Enable/disable the urgency hint on the toplevel window.

       $term->focus_in
       $term->focus_out
       $term->key_press ($state, $keycode[, $time])
       $term->key_release ($state, $keycode[, $time])
           Deliver various fake events to to terminal.

       $window_width = $term->width
       $window_height = $term->height
       $font_width = $term->fwidth
       $font_height = $term->fheight
       $font_ascent = $term->fbase
       $terminal_rows = $term->nrow
       $terminal_columns = $term->ncol
       $has_focus = $term->focus
       $is_mapped = $term->mapped
       $max_scrollback = $term->saveLines
       $nrow_plus_saveLines = $term->total_rows
       $topmost_scrollback_row = $term->top_row
           Return various integers describing terminal characteristics.

       $x_display = $term->display_id
           Return the DISPLAY used by rxvt-unicode.

       $lc_ctype = $term->locale
           Returns the LC_CTYPE category string used by this rxvt-unicode.

       $env = $term->env
           Returns a copy of the environment in effect for the terminal as a hashref similar to "\%ENV".

       @envv = $term->envv
           Returns the environment as array of strings of the form "VAR=VALUE".

       @argv = $term->argv
           Return the argument vector as this terminal, similar to @ARGV, but includes the program name as first
           element.

       $modifiermask = $term->ModLevel3Mask
       $modifiermask = $term->ModMetaMask
       $modifiermask = $term->ModNumLockMask
           Return the modifier masks corresponding to the "ISO Level 3 Shift" (often AltGr), the meta key (often
           Alt) and the num lock key, if applicable.

       $screen = $term->current_screen
           Returns the currently displayed screen (0 primary, 1 secondary).

       $cursor_is_hidden = $term->hidden_cursor
           Returns whether the cursor is currently hidden or not.

       $view_start = $term->view_start ([$newvalue])
           Returns the row number of the topmost displayed line. Maximum value is 0, which displays the normal
           terminal contents. Lower values scroll this many lines into the scrollback buffer.

       $term->want_refresh
           Requests a screen refresh. At the next opportunity, rxvt-unicode will compare the on-screen display
           with its stored representation. If they differ, it redraws the differences.

           Used after changing terminal contents to display them.

       $text = $term->ROW_t ($row_number[, $new_text[, $start_col]])
           Returns the text of the entire row with number $row_number. Row "$term->top_row" is the topmost
           terminal line, row "$term->nrow-1" is the bottommost terminal line. Nothing will be returned if a
           nonexistent line is requested.

           If $new_text is specified, it will replace characters in the current line, starting at column
           $start_col (default 0), which is useful to replace only parts of a line. The font index in the
           rendition will automatically be updated.

           $text is in a special encoding: tabs and wide characters that use more than one cell when displayed
           are padded with $urxvt::NOCHAR (chr 65535) characters. Characters with combining characters and other
           characters that do not fit into the normal text encoding will be replaced with characters in the
           private use area.

           You have to obey this encoding when changing text. The advantage is that "substr" and similar
           functions work on screen cells and not on characters.

           The methods "$term->special_encode" and "$term->special_decode" can be used to convert normal strings
           into this encoding and vice versa.

       $rend = $term->ROW_r ($row_number[, $new_rend[, $start_col]])
           Like "$term->ROW_t", but returns an arrayref with rendition bitsets. Rendition bitsets contain
           information about colour, font, font styles and similar information. See also "$term->ROW_t".

           When setting rendition, the font mask will be ignored.

           See the section on RENDITION, above.

       $length = $term->ROW_l ($row_number[, $new_length])
           Returns the number of screen cells that are in use ("the line length"). Unlike the urxvt core, this
           returns "$term->ncol" if the line is joined with the following one.

       $bool = $term->is_longer ($row_number)
           Returns true if the row is part of a multiple-row logical "line" (i.e.  joined with the following
           row), which means all characters are in use and it is continued on the next row (and possibly a
           continuation of the previous row(s)).

       $line = $term->line ($row_number)
           Create and return a new "urxvt::line" object that stores information about the logical line that row
           $row_number is part of. It supports the following methods:

           $text = $line->t ([$new_text])
               Returns or replaces the full text of the line, similar to "ROW_t"

           $rend = $line->r ([$new_rend])
               Returns or replaces the full rendition array of the line, similar to "ROW_r"

           $length = $line->l
               Returns the length of the line in cells, similar to "ROW_l".

           $rownum = $line->beg
           $rownum = $line->end
               Return the row number of the first/last row of the line, respectively.

           $offset = $line->offset_of ($row, $col)
               Returns the character offset of the given row|col pair within the logical line. Works for rows
               outside the line, too, and returns corresponding offsets outside the string.

           ($row, $col) = $line->coord_of ($offset)
               Translates a string offset into terminal coordinates again.

       $text = $term->special_encode $string
           Converts a perl string into the special encoding used by rxvt-unicode, where one character
           corresponds to one screen cell. See "$term->ROW_t" for details.

       $string = $term->special_decode $text
           Converts rxvt-unicodes text representation into a perl string. See "$term->ROW_t" for details.

       $success = $term->grab_button ($button, $modifiermask[, $window = $term->vt])
       $term->ungrab_button ($button, $modifiermask[, $window = $term->vt])
           Register/unregister a synchronous button grab. See the XGrabButton manpage.

       $success = $term->grab ($eventtime[, $sync])
           Calls XGrabPointer and XGrabKeyboard in asynchronous (default) or synchronous ($sync is true). Also
           remembers the grab timestamp.

       $term->allow_events_async
           Calls XAllowEvents with AsyncBoth for the most recent grab.

       $term->allow_events_sync
           Calls XAllowEvents with SyncBoth for the most recent grab.

       $term->allow_events_replay
           Calls XAllowEvents with both ReplayPointer and ReplayKeyboard for the most recent grab.

       $term->ungrab
           Calls XUngrabPointer and XUngrabKeyboard for the most recent grab. Is called automatically on
           evaluation errors, as it is better to lose the grab in the error case as the session.

       $atom = $term->XInternAtom ($atom_name[, $only_if_exists])
       $atom_name = $term->XGetAtomName ($atom)
       @atoms = $term->XListProperties ($window)
       ($type,$format,$octets) = $term->XGetWindowProperty ($window, $property)
       $term->XChangeProperty ($window, $property, $type, $format, $octets)
       $term->XDeleteProperty ($window, $property)
       $window = $term->DefaultRootWindow
       $term->XReparentWindow ($window, $parent, [$x, $y])
       $term->XMapWindow ($window)
       $term->XUnmapWindow ($window)
       $term->XMoveResizeWindow ($window, $x, $y, $width, $height)
       ($x, $y, $child_window) = $term->XTranslateCoordinates ($src, $dst, $x, $y)
       $term->XChangeInput ($window, $add_events[, $del_events])
       $keysym = $term->XStringToKeysym ($string)
       $string = $term->XKeysymToString ($keysym)
           Various X or X-related functions. The $term object only serves as the source of the display,
           otherwise those functions map more-or-less directly onto the X functions of the same name.

   The "urxvt::popup" Class
       $popup->add_title ($title)
           Adds a non-clickable title to the popup.

       $popup->add_separator ([$sepchr])
           Creates a separator, optionally using the character given as $sepchr.

       $popup->add_button ($text, $cb)
           Adds a clickable button to the popup. $cb is called whenever it is selected.

       $popup->add_toggle ($text, $initial_value, $cb)
           Adds a toggle/checkbox item to the popup. The callback gets called whenever it gets toggled, with a
           boolean indicating its new value as its first argument.

       $popup->show
           Displays the popup (which is initially hidden).

   The "urxvt::timer" Class
       This class implements timer watchers/events. Time is represented as a fractional number of seconds since
       the epoch. Example:

          $term->{overlay} = $term->overlay (-1, 0, 8, 1, urxvt::OVERLAY_RSTYLE, 0);
          $term->{timer} = urxvt::timer
                           ->new
                           ->interval (1)
                           ->cb (sub {
                              $term->{overlay}->set (0, 0,
                                 sprintf "%2d:%02d:%02d", (localtime urxvt::NOW)[2,1,0]);
                           });

       $timer = new urxvt::timer
           Create a new timer object in started state. It is scheduled to fire immediately.

       $timer = $timer->cb (sub { my ($timer) = @_; ... })
           Set the callback to be called when the timer triggers.

       $timer = $timer->set ($tstamp[, $interval])
           Set the time the event is generated to $tstamp (and optionally specifies a new $interval).

       $timer = $timer->interval ($interval)
           By default (and when $interval is 0), the timer will automatically stop after it has fired once. If
           $interval is non-zero, then the timer is automatically rescheduled at the given intervals.

       $timer = $timer->start
           Start the timer.

       $timer = $timer->start ($tstamp[, $interval])
           Set the event trigger time to $tstamp and start the timer. Optionally also replaces the interval.

       $timer = $timer->after ($delay[, $interval])
           Like "start", but sets the expiry timer to c<urxvt::NOW + $delay>.

       $timer = $timer->stop
           Stop the timer.

   The "urxvt::iow" Class
       This class implements io watchers/events. Example:

         $term->{socket} = ...
         $term->{iow} = urxvt::iow
                        ->new
                        ->fd (fileno $term->{socket})
                        ->events (urxvt::EV_READ)
                        ->start
                        ->cb (sub {
                          my ($iow, $revents) = @_;
                          # $revents must be 1 here, no need to check
                          sysread $term->{socket}, my $buf, 8192
                             or end-of-file;
                        });

       $iow = new urxvt::iow
           Create a new io watcher object in stopped state.

       $iow = $iow->cb (sub { my ($iow, $reventmask) = @_; ... })
           Set the callback to be called when io events are triggered. $reventmask is a bitset as described in
           the "events" method.

       $iow = $iow->fd ($fd)
           Set the file descriptor (not handle) to watch.

       $iow = $iow->events ($eventmask)
           Set the event mask to watch. The only allowed values are "urxvt::EV_READ" and "urxvt::EV_WRITE",
           which might be ORed together, or "urxvt::EV_NONE".

       $iow = $iow->start
           Start watching for requested events on the given handle.

       $iow = $iow->stop
           Stop watching for events on the given file handle.

   The "urxvt::iw" Class
       This class implements idle watchers, that get called automatically when the process is idle. They should
       return as fast as possible, after doing some useful work.

       $iw = new urxvt::iw
           Create a new idle watcher object in stopped state.

       $iw = $iw->cb (sub { my ($iw) = @_; ... })
           Set the callback to be called when the watcher triggers.

       $timer = $timer->start
           Start the watcher.

       $timer = $timer->stop
           Stop the watcher.

   The "urxvt::pw" Class
       This class implements process watchers. They create an event whenever a process exits, after which they
       stop automatically.

          my $pid = fork;
          ...
          $term->{pw} = urxvt::pw
                           ->new
                           ->start ($pid)
                           ->cb (sub {
                              my ($pw, $exit_status) = @_;
                              ...
                           });

       $pw = new urxvt::pw
           Create a new process watcher in stopped state.

       $pw = $pw->cb (sub { my ($pw, $exit_status) = @_; ... })
           Set the callback to be called when the timer triggers.

       $pw = $timer->start ($pid)
           Tells the watcher to start watching for process $pid.

       $pw = $pw->stop
           Stop the watcher.

ENVIRONMENT

   URXVT_PERL_VERBOSITY
       This variable controls the verbosity level of the perl extension. Higher numbers indicate more verbose
       output.

       == 0 - fatal messages
       >= 3 - script loading and management
       >=10 - all called hooks
       >=11 - hook return values

AUTHOR

        Marc Lehmann <schmorp@schmorp.de>
        http://software.schmorp.de/pkg/rxvt-unicode