src/termhooks.h

   1 /* Parameters and display hooks for terminal devices.
   2
   3 Copyright (C) 1985-1986, 1993-1994, 2001-2011  Free Software Foundation, Inc.
   4
   5 This file is part of GNU Emacs.
   6
   7 GNU Emacs is free software: you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation, either version 3 of the License, or
  10 (at your option) any later version.
  11
  12 GNU Emacs is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 \f
  21 /* Miscellanea.   */
  22
  23 struct glyph;
  24 struct frame;
  25 \f
  26
  27 enum scroll_bar_part {
  28   scroll_bar_above_handle,
  29   scroll_bar_handle,
  30   scroll_bar_below_handle,
  31   scroll_bar_up_arrow,
  32   scroll_bar_down_arrow,
  33   scroll_bar_to_top,
  34   scroll_bar_to_bottom,
  35   scroll_bar_end_scroll,
  36   scroll_bar_move_ratio
  37 };
  38
  39 /* If the value of the frame parameter changed, whis hook is called.
  40    For example, if going from fullscreen to not fullscreen this hook
  41    may do something OS dependent, like extended window manager hints on X11.  */
  42 extern void (*fullscreen_hook) (struct frame *f);
  43
  44 \f
  45 /* Input queue declarations and hooks.  */
  46
  47 enum event_kind
  48 {
  49   NO_EVENT,                     /* nothing happened.  This should never
  50                                    actually appear in the event queue.  */
  51
  52   ASCII_KEYSTROKE_EVENT,        /* The ASCII code is in .code, perhaps
  53                                    with modifiers applied.
  54                                    .modifiers holds the state of the
  55                                    modifier keys.
  56                                    .frame_or_window is the frame in
  57                                    which the key was typed.
  58                                    .timestamp gives a timestamp (in
  59                                    milliseconds) for the keystroke.  */
  60   MULTIBYTE_CHAR_KEYSTROKE_EVENT,       /* The multibyte char code is in .code,
  61                                    perhaps with modifiers applied.
  62                                    The others are the same as
  63                                    ASCII_KEYSTROKE_EVENT.  */
  64   NON_ASCII_KEYSTROKE_EVENT,    /* .code is a number identifying the
  65                                    function key.  A code N represents
  66                                    a key whose name is
  67                                    function_key_names[N]; function_key_names
  68                                    is a table in keyboard.c to which you
  69                                    should feel free to add missing keys.
  70                                    .modifiers holds the state of the
  71                                    modifier keys.
  72                                    .frame_or_window is the frame in
  73                                    which the key was typed.
  74                                    .timestamp gives a timestamp (in
  75                                    milliseconds) for the keystroke.  */
  76   TIMER_EVENT,                  /* A timer fired.  */
  77   MOUSE_CLICK_EVENT,            /* The button number is in .code; it must
  78                                    be >= 0 and < NUM_MOUSE_BUTTONS, defined
  79                                    below.
  80                                    .modifiers holds the state of the
  81                                    modifier keys.
  82                                    .x and .y give the mouse position,
  83                                    in characters, within the window.
  84                                    .frame_or_window gives the frame
  85                                    the mouse click occurred in.
  86                                    .timestamp gives a timestamp (in
  87                                    milliseconds) for the click.  */
  88   WHEEL_EVENT,                  /* A wheel event is generated by a
  89                                    wheel on a mouse (e.g., MS
  90                                    Intellimouse).
  91                                    .modifiers holds the rotate
  92                                    direction (up or down), and the
  93                                    state of the modifier keys.
  94                                    .x and .y give the mouse position,
  95                                    in characters, within the window.
  96                                    .frame_or_window gives the frame
  97                                    the wheel event occurred in.
  98                                    .timestamp gives a timestamp (in
  99                                    milliseconds) for the event.  */
 100   HORIZ_WHEEL_EVENT,            /* A wheel event generated by a second
 101                                    horizontal wheel that is present on some
 102                                    mice. See WHEEL_EVENT.  */
 103 #if defined (WINDOWSNT)
 104   LANGUAGE_CHANGE_EVENT,        /* A LANGUAGE_CHANGE_EVENT is
 105                                    generated on WINDOWSNT or Mac OS
 106                                    when the keyboard layout or input
 107                                    language is changed by the
 108                                    user.  */
 109 #endif
 110   SCROLL_BAR_CLICK_EVENT,       /* .code gives the number of the mouse button
 111                                    that was clicked.
 112                                    .modifiers holds the state of the modifier
 113                                    keys.
 114                                    .part is a lisp symbol indicating which
 115                                    part of the scroll bar got clicked.
 116                                    .x gives the distance from the start of the
 117                                    scroll bar of the click; .y gives the total
 118                                    length of the scroll bar.
 119                                    .frame_or_window gives the window
 120                                    whose scroll bar was clicked in.
 121                                    .timestamp gives a timestamp (in
 122                                    milliseconds) for the click.  */
 123   SELECTION_REQUEST_EVENT,      /* Another X client wants a selection from us.
 124                                    See `struct selection_input_event'.  */
 125   SELECTION_CLEAR_EVENT,        /* Another X client cleared our selection.  */
 126   BUFFER_SWITCH_EVENT,          /* A process filter has switched buffers.  */
 127   DELETE_WINDOW_EVENT,          /* An X client said "delete this window".  */
 128   MENU_BAR_EVENT,               /* An event generated by the menu bar.
 129                                    The frame_or_window field's cdr holds the
 130                                    Lisp-level event value.
 131                                    (Only the toolkit version uses these.)  */
 132   ICONIFY_EVENT,                /* An X client iconified this window.  */
 133   DEICONIFY_EVENT,              /* An X client deiconified this window.  */
 134   MENU_BAR_ACTIVATE_EVENT,      /* A button press in the menu bar
 135                                    (toolkit version only).  */
 136   DRAG_N_DROP_EVENT,            /* A drag-n-drop event is generated when
 137                                    files selected outside of Emacs are dropped
 138                                    onto an Emacs window.
 139                                    .modifiers holds the state of the
 140                                    modifier keys.
 141                                    .x and .y give the mouse position,
 142                                    in characters, within the window.
 143                                    .frame_or_window is the frame in
 144                                    which the drop was made.
 145                                    .arg is a platform-dependent
 146                                    representation of the dropped items.
 147                                    .timestamp gives a timestamp (in
 148                                    milliseconds) for the click.  */
 149   USER_SIGNAL_EVENT,            /* A user signal.
 150                                    code is a number identifying it,
 151                                    index into lispy_user_signals.  */
 152
 153   /* Help events.  Member `frame_or_window' of the input_event is the
 154      frame on which the event occurred, and member `arg' contains
 155      the help to show.  */
 156   HELP_EVENT,
 157
 158   /* An event from a tool-bar.  Member `arg' of the input event
 159      contains the tool-bar item selected.  If `frame_or_window'
 160      and `arg' are equal, this is a prefix event.  */
 161   TOOL_BAR_EVENT,
 162
 163   /* Queued from XTread_socket on FocusIn events.  Translated into
 164      `switch-frame' events in kbd_buffer_get_event, if necessary.  */
 165   FOCUS_IN_EVENT,
 166
 167   /* Generated when mouse moves over window not currently selected.  */
 168   SELECT_WINDOW_EVENT,
 169
 170   /* Queued from XTread_socket when session manager sends
 171      save yourself before shutdown. */
 172   SAVE_SESSION_EVENT
 173
 174 #ifdef HAVE_GPM
 175   , GPM_CLICK_EVENT
 176 #endif
 177
 178 #ifdef HAVE_DBUS
 179   , DBUS_EVENT
 180 #endif
 181
 182   , CONFIG_CHANGED_EVENT
 183
 184 #ifdef WINDOWSNT
 185   /* Generated when an APPCOMMAND event is received, in response to
 186      Multimedia or Internet buttons on some keyboards.
 187      Such keys are available as normal function keys on X through the
 188      Xkeyboard extension.
 189      On Windows, some of them get mapped to normal function key events,
 190      but others need to be handled by APPCOMMAND. Handling them all as
 191      APPCOMMAND events means they can be disabled
 192      (w32-pass-multimedia-buttons-to-system), important on Windows since
 193      the system never sees these keys if Emacs claims to handle them.
 194      On X, the window manager seems to grab the keys it wants
 195      first, so this is not a problem there.  */
 196   , MULTIMEDIA_KEY_EVENT
 197 #endif
 198
 199 #ifdef HAVE_NS
 200   /* Generated when native multi-keystroke input method is used to modify
 201      tentative or indicative text display. */
 202   , NS_TEXT_EVENT
 203   /* Non-key system events (e.g. application menu events) */
 204   , NS_NONKEY_EVENT
 205 #endif
 206
 207 };
 208
 209 /* If a struct input_event has a kind which is SELECTION_REQUEST_EVENT
 210    or SELECTION_CLEAR_EVENT, then its contents are really described
 211    by `struct selection_input_event'; see xterm.h.  */
 212
 213 /* The keyboard input buffer is an array of these structures.  Each one
 214    represents some sort of input event - a keystroke, a mouse click, or
 215    a window system event.  These get turned into their lispy forms when
 216    they are removed from the event queue.  */
 217
 218 struct input_event
 219 {
 220   /* What kind of event was this?  */
 221   enum event_kind kind;
 222
 223   /* For an ASCII_KEYSTROKE_EVENT and MULTIBYTE_CHAR_KEYSTROKE_EVENT,
 224      this is the character.
 225      For a NON_ASCII_KEYSTROKE_EVENT, this is the keysym code.
 226      For a mouse event, this is the button number.
 227      For a HELP_EVENT, this is the position within the object
 228       (stored in ARG below) where the help was found.  */
 229   /* In WindowsNT, for a mouse wheel event, this is the delta.  */
 230   EMACS_INT code;
 231   enum scroll_bar_part part;
 232
 233   int modifiers;                /* See enum below for interpretation.  */
 234
 235   Lisp_Object x, y;
 236   unsigned long timestamp;
 237
 238   /* This is padding just to put the frame_or_window field
 239      past the size of struct selection_input_event.  */
 240   int *padding[2];
 241
 242   /* This field is copied into a vector while the event is in the queue,
 243      so that garbage collections won't kill it.  */
 244   /* In a menu_bar_event, this is a cons cell whose car is the frame
 245      and whose cdr is the Lisp object that is the event's value.  */
 246   /* This field is last so that struct selection_input_event
 247      does not overlap with it.  */
 248   Lisp_Object frame_or_window;
 249
 250   /* Additional event argument.  This is used for TOOL_BAR_EVENTs and
 251      HELP_EVENTs and avoids calling Fcons during signal handling.  */
 252   Lisp_Object arg;
 253 };
 254
 255 #define EVENT_INIT(event) memset (&(event), 0, sizeof (struct input_event))
 256
 257 /* Bits in the modifiers member of the input_event structure.
 258    Note that reorder_modifiers assumes that the bits are in canonical
 259    order.
 260
 261    The modifiers applied to mouse clicks are rather ornate.  The
 262    window-system-specific code should store mouse clicks with
 263    up_modifier or down_modifier set.  Having an explicit down modifier
 264    simplifies some of window-system-independent code; without it, the
 265    code would have to recognize down events by checking if the event
 266    is a mouse click lacking the click and drag modifiers.
 267
 268    The window-system independent code turns all up_modifier events
 269    bits into drag_modifier, click_modifier, double_modifier, or
 270    triple_modifier events.  The click_modifier has no written
 271    representation in the names of the symbols used as event heads,
 272    but it does appear in the Qevent_symbol_components property of the
 273    event heads.  */
 274 enum {
 275   up_modifier   =   1,          /* Only used on mouse buttons - always
 276                                    turned into a click or a drag modifier
 277                                    before lisp code sees the event.  */
 278   down_modifier =   2,          /* Only used on mouse buttons.  */
 279   drag_modifier =   4,          /* This is never used in the event
 280                                    queue; it's only used internally by
 281                                    the window-system-independent code.  */
 282   click_modifier=   8,          /* See drag_modifier.  */
 283   double_modifier= 16,          /* See drag_modifier.  */
 284   triple_modifier= 32,          /* See drag_modifier.  */
 285
 286   /* The next four modifier bits are used also in keyboard events at
 287      the Lisp level.
 288
 289      It's probably not the greatest idea to use the 2^23 bit for any
 290      modifier.  It may or may not be the sign bit, depending on
 291      VALBITS, so using it to represent a modifier key means that
 292      characters thus modified have different integer equivalents
 293      depending on the architecture they're running on.  Oh, and
 294      applying XINT to a character whose 2^23 bit is set sign-extends
 295      it, so you get a bunch of bits in the mask you didn't want.
 296
 297      The CHAR_ macros are defined in lisp.h.  */
 298   alt_modifier  =  CHAR_ALT,    /* Under X, the XK_Alt_[LR] keysyms.  */
 299   super_modifier=  CHAR_SUPER,  /* Under X, the XK_Super_[LR] keysyms.  */
 300   hyper_modifier=  CHAR_HYPER,  /* Under X, the XK_Hyper_[LR] keysyms.  */
 301   shift_modifier=  CHAR_SHIFT,
 302   ctrl_modifier =  CHAR_CTL,
 303   meta_modifier =  CHAR_META    /* Under X, the XK_Meta_[LR] keysyms.  */
 304 };
 305
 306 #ifdef HAVE_GPM
 307 #include <gpm.h>
 308 extern int handle_one_term_event (struct tty_display_info *, Gpm_Event *, struct input_event *);
 309 #ifndef HAVE_WINDOW_SYSTEM
 310 extern void term_mouse_moveto (int, int);
 311 #endif
 312
 313 /* The device for which we have enabled gpm support.  */
 314 extern struct tty_display_info *gpm_tty;
 315 #endif
 316
 317 \f
 318 struct ns_display_info;
 319 struct x_display_info;
 320 struct w32_display_info;
 321
 322 /* Terminal-local parameters. */
 323 struct terminal
 324 {
 325   /* The first two fields are really the header of a vector */
 326   /* The terminal code does not refer to them.  */
 327   EMACS_UINT size;
 328   struct Lisp_Vector *vec_next;
 329
 330   /* Parameter alist of this terminal.  */
 331   Lisp_Object param_alist;
 332
 333   /* List of charsets supported by the terminal.  It is set by
 334      Fset_terminal_coding_system_internal along with
 335      the member terminal_coding.  */
 336   Lisp_Object charset_list;
 337
 338   /* All fields before `next_terminal' should be Lisp_Object and are traced
 339      by the GC.  All fields afterwards are ignored by the GC.  */
 340
 341   /* Chain of all terminal devices. */
 342   struct terminal *next_terminal;
 343
 344   /* Unique id for this terminal device. */
 345   int id;
 346
 347   /* The number of frames that are on this terminal. */
 348   int reference_count;
 349
 350   /* The type of the terminal device. */
 351   enum output_method type;
 352
 353   /* The name of the terminal device.  Do not use this to uniquely
 354      identify a terminal; the same device may be opened multiple
 355      times. */
 356   char *name;
 357
 358   /* The terminal's keyboard object. */
 359   struct kboard *kboard;
 360
 361 #ifdef HAVE_WINDOW_SYSTEM
 362   /* Cache of images.  */
 363   struct image_cache *image_cache;
 364 #endif /* HAVE_WINDOW_SYSTEM */
 365
 366   /* Device-type dependent data shared amongst all frames on this terminal. */
 367   union display_info
 368   {
 369     struct tty_display_info *tty;     /* termchar.h */
 370     struct x_display_info *x;         /* xterm.h */
 371     struct w32_display_info *w32;     /* w32term.h */
 372     struct ns_display_info *ns;       /* nsterm.h */
 373   } display_info;
 374
 375 \f
 376   /* Coding-system to be used for encoding terminal output.  This
 377      structure contains information of a coding-system specified by
 378      the function `set-terminal-coding-system'.  Also see
 379      `safe_terminal_coding' in coding.h.  */
 380   struct coding_system *terminal_coding;
 381
 382   /* Coding-system of what is sent from terminal keyboard.  This
 383      structure contains information of a coding-system specified by
 384      the function `set-keyboard-coding-system'.  */
 385   struct coding_system *keyboard_coding;
 386
 387   /* Terminal characteristics. */
 388   /* XXX Are these really used on non-termcap displays? */
 389
 390   int must_write_spaces;        /* Nonzero means spaces in the text must
 391                                    actually be output; can't just skip over
 392                                    some columns to leave them blank.  */
 393   int fast_clear_end_of_line;   /* Nonzero means terminal has a `ce' string */
 394
 395   int line_ins_del_ok;          /* Terminal can insert and delete lines */
 396   int char_ins_del_ok;          /* Terminal can insert and delete chars */
 397   int scroll_region_ok;         /* Terminal supports setting the scroll
 398                                    window */
 399   int scroll_region_cost;       /* Cost of setting the scroll window,
 400                                    measured in characters. */
 401   int memory_below_frame;       /* Terminal remembers lines scrolled
 402                                    off bottom */
 403
 404 #if 0  /* These are not used anywhere. */
 405   /* EMACS_INT baud_rate; */    /* Output speed in baud */
 406   int min_padding_speed;        /* Speed below which no padding necessary. */
 407   int dont_calculate_costs;     /* Nonzero means don't bother computing
 408                                    various cost tables; we won't use them. */
 409 #endif
 410
 411 \f
 412   /* Window-based redisplay interface for this device (0 for tty
 413      devices). */
 414   struct redisplay_interface *rif;
 415
 416   /* Frame-based redisplay interface. */
 417
 418   /* Text display hooks.  */
 419
 420   void (*cursor_to_hook) (struct frame *f, int vpos, int hpos);
 421   void (*raw_cursor_to_hook) (struct frame *, int, int);
 422
 423   void (*clear_to_end_hook) (struct frame *);
 424   void (*clear_frame_hook) (struct frame *);
 425   void (*clear_end_of_line_hook) (struct frame *, int);
 426
 427   void (*ins_del_lines_hook) (struct frame *f, int, int);
 428
 429   void (*insert_glyphs_hook) (struct frame *f, struct glyph *s, int n);
 430   void (*write_glyphs_hook) (struct frame *f, struct glyph *s, int n);
 431   void (*delete_glyphs_hook) (struct frame *, int);
 432
 433   void (*ring_bell_hook) (struct frame *f);
 434   void (*toggle_invisible_pointer_hook) (struct frame *f, int invisible);
 435
 436   void (*reset_terminal_modes_hook) (struct terminal *);
 437   void (*set_terminal_modes_hook) (struct terminal *);
 438
 439   void (*update_begin_hook) (struct frame *);
 440   void (*update_end_hook) (struct frame *);
 441   void (*set_terminal_window_hook) (struct frame *, int);
 442
 443   /* Multi-frame and mouse support hooks.  */
 444
 445   /* Return the current position of the mouse.
 446
 447      Set *f to the frame the mouse is in, or zero if the mouse is in no
 448      Emacs frame.  If it is set to zero, all the other arguments are
 449      garbage.
 450
 451      If the motion started in a scroll bar, set *bar_window to the
 452      scroll bar's window, *part to the part the mouse is currently over,
 453      *x to the position of the mouse along the scroll bar, and *y to the
 454      overall length of the scroll bar.
 455
 456      Otherwise, set *bar_window to Qnil, and *x and *y to the column and
 457      row of the character cell the mouse is over.
 458
 459      Set *time to the time the mouse was at the returned position.
 460
 461      This should clear mouse_moved until the next motion
 462      event arrives.  */
 463   void (*mouse_position_hook) (struct frame **f, int,
 464                                Lisp_Object *bar_window,
 465                                enum scroll_bar_part *part,
 466                                Lisp_Object *x,
 467                                Lisp_Object *y,
 468                                unsigned long *);
 469
 470   /* The window system handling code should set this if the mouse has
 471      moved since the last call to the mouse_position_hook.  Calling that
 472      hook should clear this.  */
 473   int mouse_moved;
 474
 475   /* When a frame's focus redirection is changed, this hook tells the
 476      window system code to re-decide where to put the highlight.  Under
 477      X, this means that Emacs lies about where the focus is.  */
 478   void (*frame_rehighlight_hook) (struct frame *);
 479
 480   /* If we're displaying frames using a window system that can stack
 481      frames on top of each other, this hook allows you to bring a frame
 482      to the front, or bury it behind all the other windows.  If this
 483      hook is zero, that means the terminal we're displaying on doesn't
 484      support overlapping frames, so there's no need to raise or lower
 485      anything.
 486
 487      If RAISE_FLAG is non-zero, F is brought to the front, before all other
 488      windows.  If RAISE_FLAG is zero, F is sent to the back, behind all other
 489      windows.  */
 490   void (*frame_raise_lower_hook) (struct frame *f, int raise_flag);
 491
 492   /* If the value of the frame parameter changed, whis hook is called.
 493      For example, if going from fullscreen to not fullscreen this hook
 494      may do something OS dependent, like extended window manager hints on X11.  */
 495   void (*fullscreen_hook) (struct frame *f);
 496
 497   \f
 498   /* Scroll bar hooks.  */
 499
 500   /* The representation of scroll bars is determined by the code which
 501      implements them, except for one thing: they must be represented by
 502      lisp objects.  This allows us to place references to them in
 503      Lisp_Windows without worrying about those references becoming
 504      dangling references when the scroll bar is destroyed.
 505
 506      The window-system-independent portion of Emacs just refers to
 507      scroll bars via their windows, and never looks inside the scroll bar
 508      representation; it always uses hook functions to do all the
 509      scroll bar manipulation it needs.
 510
 511      The `vertical_scroll_bar' field of a Lisp_Window refers to that
 512      window's scroll bar, or is nil if the window doesn't have a
 513      scroll bar.
 514
 515      The `scroll_bars' and `condemned_scroll_bars' fields of a Lisp_Frame
 516      are free for use by the scroll bar implementation in any way it sees
 517      fit.  They are marked by the garbage collector.  */
 518
 519
 520   /* Set the vertical scroll bar for WINDOW to have its upper left corner
 521      at (TOP, LEFT), and be LENGTH rows high.  Set its handle to
 522      indicate that we are displaying PORTION characters out of a total
 523      of WHOLE characters, starting at POSITION.  If WINDOW doesn't yet
 524      have a scroll bar, create one for it.  */
 525   void (*set_vertical_scroll_bar_hook) (struct window *window,
 526                                         int portion, int whole,
 527                                         int position);
 528
 529
 530   /* The following three hooks are used when we're doing a thorough
 531      redisplay of the frame.  We don't explicitly know which scroll bars
 532      are going to be deleted, because keeping track of when windows go
 533      away is a real pain - can you say set-window-configuration?
 534      Instead, we just assert at the beginning of redisplay that *all*
 535      scroll bars are to be removed, and then save scroll bars from the
 536      fiery pit when we actually redisplay their window.  */
 537
 538   /* Arrange for all scroll bars on FRAME to be removed at the next call
 539      to `*judge_scroll_bars_hook'.  A scroll bar may be spared if
 540      `*redeem_scroll_bar_hook' is applied to its window before the judgement.
 541
 542      This should be applied to each frame each time its window tree is
 543      redisplayed, even if it is not displaying scroll bars at the moment;
 544      if the HAS_SCROLL_BARS flag has just been turned off, only calling
 545      this and the judge_scroll_bars_hook will get rid of them.
 546
 547      If non-zero, this hook should be safe to apply to any frame,
 548      whether or not it can support scroll bars, and whether or not it is
 549      currently displaying them.  */
 550   void (*condemn_scroll_bars_hook) (struct frame *frame);
 551
 552   /* Unmark WINDOW's scroll bar for deletion in this judgement cycle.
 553      Note that it's okay to redeem a scroll bar that is not condemned.  */
 554   void (*redeem_scroll_bar_hook) (struct window *window);
 555
 556   /* Remove all scroll bars on FRAME that haven't been saved since the
 557      last call to `*condemn_scroll_bars_hook'.
 558
 559      This should be applied to each frame after each time its window
 560      tree is redisplayed, even if it is not displaying scroll bars at the
 561      moment; if the HAS_SCROLL_BARS flag has just been turned off, only
 562      calling this and condemn_scroll_bars_hook will get rid of them.
 563
 564      If non-zero, this hook should be safe to apply to any frame,
 565      whether or not it can support scroll bars, and whether or not it is
 566      currently displaying them.  */
 567   void (*judge_scroll_bars_hook) (struct frame *FRAME);
 568
 569 \f
 570   /* Called to read input events.
 571
 572      TERMINAL indicates which terminal device to read from.  Input
 573      events should be read into BUF, the size of which is given in
 574      SIZE.  EXPECTED is non-zero if the caller suspects that new input
 575      is available.
 576
 577      A positive return value indicates that that many input events
 578      where read into BUF.
 579      Zero means no events were immediately available.
 580      A value of -1 means a transient read error, while -2 indicates
 581      that the device was closed (hangup), and it should be deleted.
 582
 583      XXX Please note that a non-zero value of EXPECTED only means that
 584      there is available input on at least one of the currently opened
 585      terminal devices -- but not necessarily on this device.
 586      Therefore, in most cases EXPECTED should be simply ignored.
 587
 588      XXX This documentation needs to be updated.  */
 589   int (*read_socket_hook) (struct terminal *terminal,
 590                            int expected,
 591                            struct input_event *hold_quit);
 592
 593   /* Called when a frame's display becomes entirely up to date.  */
 594   void (*frame_up_to_date_hook) (struct frame *);
 595
 596 \f
 597   /* Called to delete the device-specific portions of a frame that is
 598      on this terminal device. */
 599   void (*delete_frame_hook) (struct frame *);
 600
 601   /* Called after the last frame on this terminal is deleted, or when
 602      the display device was closed (hangup).
 603
 604      If this is NULL, then the generic delete_terminal is called
 605      instead.  Otherwise the hook must call delete_terminal itself.
 606
 607      The hook must check for and close any live frames that are still
 608      on the terminal.  delete_frame ensures that there are no live
 609      frames on the terminal when it calls this hook, so infinite
 610      recursion is prevented.  */
 611   void (*delete_terminal_hook) (struct terminal *);
 612 };
 613
 614
 615 /* Chain of all terminal devices currently in use. */
 616 extern struct terminal *terminal_list;
 617
 618 #define FRAME_MUST_WRITE_SPACES(f) ((f)->terminal->must_write_spaces)
 619 #define FRAME_FAST_CLEAR_END_OF_LINE(f) ((f)->terminal->fast_clear_end_of_line)
 620 #define FRAME_LINE_INS_DEL_OK(f) ((f)->terminal->line_ins_del_ok)
 621 #define FRAME_CHAR_INS_DEL_OK(f) ((f)->terminal->char_ins_del_ok)
 622 #define FRAME_SCROLL_REGION_OK(f) ((f)->terminal->scroll_region_ok)
 623 #define FRAME_SCROLL_REGION_COST(f) ((f)->terminal->scroll_region_cost)
 624 #define FRAME_MEMORY_BELOW_FRAME(f) ((f)->terminal->memory_below_frame)
 625
 626 #define FRAME_TERMINAL_CODING(f) ((f)->terminal->terminal_coding)
 627 #define FRAME_KEYBOARD_CODING(f) ((f)->terminal->keyboard_coding)
 628
 629 #define TERMINAL_TERMINAL_CODING(d) ((d)->terminal_coding)
 630 #define TERMINAL_KEYBOARD_CODING(d) ((d)->keyboard_coding)
 631
 632 #define FRAME_RIF(f) ((f)->terminal->rif)
 633
 634 #define FRAME_TERMINAL(f) ((f)->terminal)
 635
 636 /* Return true if the terminal device is not suspended. */
 637 #define TERMINAL_ACTIVE_P(d) (((d)->type != output_termcap && (d)->type !=output_msdos_raw) || (d)->display_info.tty->input)
 638
 639 extern struct terminal *get_terminal (Lisp_Object terminal, int);
 640 extern struct terminal *create_terminal (void);
 641 extern void delete_terminal (struct terminal *);
 642
 643 /* The initial terminal device, created by initial_term_init. */
 644 extern struct terminal *initial_terminal;
 645
 646 extern unsigned char *encode_terminal_code (struct glyph *, int,
 647                                             struct coding_system *);
 648
 649 #ifdef HAVE_GPM
 650 extern void close_gpm (int gpm_fd);
 651 #endif