gdb/thread.c

   1 /* Multi-process/thread control for GDB, the GNU debugger.
   2
   3    Copyright (C) 1986, 1987, 1988, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4    2000, 2001, 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
   5
   6    Contributed by Lynx Real-Time Systems, Inc.  Los Gatos, CA.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #include "defs.h"
  24 #include "symtab.h"
  25 #include "frame.h"
  26 #include "inferior.h"
  27 #include "environ.h"
  28 #include "value.h"
  29 #include "target.h"
  30 #include "gdbthread.h"
  31 #include "exceptions.h"
  32 #include "command.h"
  33 #include "gdbcmd.h"
  34 #include "regcache.h"
  35 #include "gdb.h"
  36 #include "gdb_string.h"
  37
  38 #include <ctype.h>
  39 #include <sys/types.h>
  40 #include <signal.h>
  41 #include "ui-out.h"
  42
  43 /* Definition of struct thread_info exported to gdbthread.h */
  44
  45 /* Prototypes for exported functions. */
  46
  47 void _initialize_thread (void);
  48
  49 /* Prototypes for local functions. */
  50
  51 static struct thread_info *thread_list = NULL;
  52 static int highest_thread_num;
  53
  54 static struct thread_info *find_thread_id (int num);
  55
  56 static void thread_command (char *tidstr, int from_tty);
  57 static void thread_apply_all_command (char *, int);
  58 static int thread_alive (struct thread_info *);
  59 static void info_threads_command (char *, int);
  60 static void thread_apply_command (char *, int);
  61 static void restore_current_thread (ptid_t);
  62 static void switch_to_thread (ptid_t ptid);
  63 static void prune_threads (void);
  64 static struct cleanup *make_cleanup_restore_current_thread (ptid_t,
  65                                                             struct frame_id);
  66
  67 void
  68 delete_step_resume_breakpoint (void *arg)
  69 {
  70   struct breakpoint **breakpointp = (struct breakpoint **) arg;
  71   struct thread_info *tp;
  72
  73   if (*breakpointp != NULL)
  74     {
  75       delete_breakpoint (*breakpointp);
  76       for (tp = thread_list; tp; tp = tp->next)
  77         if (tp->step_resume_breakpoint == *breakpointp)
  78           tp->step_resume_breakpoint = NULL;
  79
  80       *breakpointp = NULL;
  81     }
  82 }
  83
  84 static void
  85 free_thread (struct thread_info *tp)
  86 {
  87   /* NOTE: this will take care of any left-over step_resume breakpoints,
  88      but not any user-specified thread-specific breakpoints. */
  89   if (tp->step_resume_breakpoint)
  90     delete_breakpoint (tp->step_resume_breakpoint);
  91
  92   /* FIXME: do I ever need to call the back-end to give it a
  93      chance at this private data before deleting the thread?  */
  94   if (tp->private)
  95     xfree (tp->private);
  96
  97   xfree (tp);
  98 }
  99
 100 void
 101 init_thread_list (void)
 102 {
 103   struct thread_info *tp, *tpnext;
 104
 105   highest_thread_num = 0;
 106   if (!thread_list)
 107     return;
 108
 109   for (tp = thread_list; tp; tp = tpnext)
 110     {
 111       tpnext = tp->next;
 112       free_thread (tp);
 113     }
 114
 115   thread_list = NULL;
 116 }
 117
 118 /* add_thread now returns a pointer to the new thread_info,
 119    so that back_ends can initialize their private data.  */
 120
 121 struct thread_info *
 122 add_thread (ptid_t ptid)
 123 {
 124   struct thread_info *tp;
 125
 126   tp = (struct thread_info *) xmalloc (sizeof (*tp));
 127   memset (tp, 0, sizeof (*tp));
 128   tp->ptid = ptid;
 129   tp->num = ++highest_thread_num;
 130   tp->next = thread_list;
 131   thread_list = tp;
 132   return tp;
 133 }
 134
 135 void
 136 delete_thread (ptid_t ptid)
 137 {
 138   struct thread_info *tp, *tpprev;
 139
 140   tpprev = NULL;
 141
 142   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 143     if (ptid_equal (tp->ptid, ptid))
 144       break;
 145
 146   if (!tp)
 147     return;
 148
 149   if (tpprev)
 150     tpprev->next = tp->next;
 151   else
 152     thread_list = tp->next;
 153
 154   free_thread (tp);
 155 }
 156
 157 static struct thread_info *
 158 find_thread_id (int num)
 159 {
 160   struct thread_info *tp;
 161
 162   for (tp = thread_list; tp; tp = tp->next)
 163     if (tp->num == num)
 164       return tp;
 165
 166   return NULL;
 167 }
 168
 169 /* Find a thread_info by matching PTID.  */
 170 struct thread_info *
 171 find_thread_pid (ptid_t ptid)
 172 {
 173   struct thread_info *tp;
 174
 175   for (tp = thread_list; tp; tp = tp->next)
 176     if (ptid_equal (tp->ptid, ptid))
 177       return tp;
 178
 179   return NULL;
 180 }
 181
 182 /*
 183  * Thread iterator function.
 184  *
 185  * Calls a callback function once for each thread, so long as
 186  * the callback function returns false.  If the callback function
 187  * returns true, the iteration will end and the current thread
 188  * will be returned.  This can be useful for implementing a
 189  * search for a thread with arbitrary attributes, or for applying
 190  * some operation to every thread.
 191  *
 192  * FIXME: some of the existing functionality, such as
 193  * "Thread apply all", might be rewritten using this functionality.
 194  */
 195
 196 struct thread_info *
 197 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 198                       void *data)
 199 {
 200   struct thread_info *tp;
 201
 202   for (tp = thread_list; tp; tp = tp->next)
 203     if ((*callback) (tp, data))
 204       return tp;
 205
 206   return NULL;
 207 }
 208
 209 int
 210 valid_thread_id (int num)
 211 {
 212   struct thread_info *tp;
 213
 214   for (tp = thread_list; tp; tp = tp->next)
 215     if (tp->num == num)
 216       return 1;
 217
 218   return 0;
 219 }
 220
 221 int
 222 pid_to_thread_id (ptid_t ptid)
 223 {
 224   struct thread_info *tp;
 225
 226   for (tp = thread_list; tp; tp = tp->next)
 227     if (ptid_equal (tp->ptid, ptid))
 228       return tp->num;
 229
 230   return 0;
 231 }
 232
 233 ptid_t
 234 thread_id_to_pid (int num)
 235 {
 236   struct thread_info *thread = find_thread_id (num);
 237   if (thread)
 238     return thread->ptid;
 239   else
 240     return pid_to_ptid (-1);
 241 }
 242
 243 int
 244 in_thread_list (ptid_t ptid)
 245 {
 246   struct thread_info *tp;
 247
 248   for (tp = thread_list; tp; tp = tp->next)
 249     if (ptid_equal (tp->ptid, ptid))
 250       return 1;
 251
 252   return 0;                     /* Never heard of 'im */
 253 }
 254
 255 /* Print a list of thread ids currently known, and the total number of
 256    threads. To be used from within catch_errors. */
 257 static int
 258 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 259 {
 260   struct thread_info *tp;
 261   int num = 0;
 262   struct cleanup *cleanup_chain;
 263
 264   prune_threads ();
 265   target_find_new_threads ();
 266
 267   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 268
 269   for (tp = thread_list; tp; tp = tp->next)
 270     {
 271       num++;
 272       ui_out_field_int (uiout, "thread-id", tp->num);
 273     }
 274
 275   do_cleanups (cleanup_chain);
 276   ui_out_field_int (uiout, "number-of-threads", num);
 277   return GDB_RC_OK;
 278 }
 279
 280 /* Official gdblib interface function to get a list of thread ids and
 281    the total number. */
 282 enum gdb_rc
 283 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 284 {
 285   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 286                                  error_message, RETURN_MASK_ALL) < 0)
 287     return GDB_RC_FAIL;
 288   return GDB_RC_OK;
 289 }
 290
 291 /* Load infrun state for the thread PID.  */
 292
 293 void
 294 load_infrun_state (ptid_t ptid,
 295                    CORE_ADDR *prev_pc,
 296                    int *trap_expected,
 297                    struct breakpoint **step_resume_breakpoint,
 298                    CORE_ADDR *step_range_start,
 299                    CORE_ADDR *step_range_end,
 300                    struct frame_id *step_frame_id,
 301                    int *handling_longjmp,
 302                    int *another_trap,
 303                    int *stepping_through_solib_after_catch,
 304                    bpstat *stepping_through_solib_catchpoints,
 305                    int *current_line,
 306                    struct symtab **current_symtab)
 307 {
 308   struct thread_info *tp;
 309
 310   /* If we can't find the thread, then we're debugging a single threaded
 311      process.  No need to do anything in that case.  */
 312   tp = find_thread_id (pid_to_thread_id (ptid));
 313   if (tp == NULL)
 314     return;
 315
 316   *prev_pc = tp->prev_pc;
 317   *trap_expected = tp->trap_expected;
 318   *step_resume_breakpoint = tp->step_resume_breakpoint;
 319   *step_range_start = tp->step_range_start;
 320   *step_range_end = tp->step_range_end;
 321   *step_frame_id = tp->step_frame_id;
 322   *handling_longjmp = tp->handling_longjmp;
 323   *another_trap = tp->another_trap;
 324   *stepping_through_solib_after_catch =
 325     tp->stepping_through_solib_after_catch;
 326   *stepping_through_solib_catchpoints =
 327     tp->stepping_through_solib_catchpoints;
 328   *current_line = tp->current_line;
 329   *current_symtab = tp->current_symtab;
 330 }
 331
 332 /* Save infrun state for the thread PID.  */
 333
 334 void
 335 save_infrun_state (ptid_t ptid,
 336                    CORE_ADDR prev_pc,
 337                    int trap_expected,
 338                    struct breakpoint *step_resume_breakpoint,
 339                    CORE_ADDR step_range_start,
 340                    CORE_ADDR step_range_end,
 341                    const struct frame_id *step_frame_id,
 342                    int handling_longjmp,
 343                    int another_trap,
 344                    int stepping_through_solib_after_catch,
 345                    bpstat stepping_through_solib_catchpoints,
 346                    int current_line,
 347                    struct symtab *current_symtab)
 348 {
 349   struct thread_info *tp;
 350
 351   /* If we can't find the thread, then we're debugging a single-threaded
 352      process.  Nothing to do in that case.  */
 353   tp = find_thread_id (pid_to_thread_id (ptid));
 354   if (tp == NULL)
 355     return;
 356
 357   tp->prev_pc = prev_pc;
 358   tp->trap_expected = trap_expected;
 359   tp->step_resume_breakpoint = step_resume_breakpoint;
 360   tp->step_range_start = step_range_start;
 361   tp->step_range_end = step_range_end;
 362   tp->step_frame_id = (*step_frame_id);
 363   tp->handling_longjmp = handling_longjmp;
 364   tp->another_trap = another_trap;
 365   tp->stepping_through_solib_after_catch = stepping_through_solib_after_catch;
 366   tp->stepping_through_solib_catchpoints = stepping_through_solib_catchpoints;
 367   tp->current_line = current_line;
 368   tp->current_symtab = current_symtab;
 369 }
 370
 371 /* Return true if TP is an active thread. */
 372 static int
 373 thread_alive (struct thread_info *tp)
 374 {
 375   if (PIDGET (tp->ptid) == -1)
 376     return 0;
 377   if (!target_thread_alive (tp->ptid))
 378     {
 379       tp->ptid = pid_to_ptid (-1);      /* Mark it as dead */
 380       return 0;
 381     }
 382   return 1;
 383 }
 384
 385 static void
 386 prune_threads (void)
 387 {
 388   struct thread_info *tp, *next;
 389
 390   for (tp = thread_list; tp; tp = next)
 391     {
 392       next = tp->next;
 393       if (!thread_alive (tp))
 394         delete_thread (tp->ptid);
 395     }
 396 }
 397
 398 /* Print information about currently known threads
 399
 400  * Note: this has the drawback that it _really_ switches
 401  *       threads, which frees the frame cache.  A no-side
 402  *       effects info-threads command would be nicer.
 403  */
 404
 405 static void
 406 info_threads_command (char *arg, int from_tty)
 407 {
 408   struct thread_info *tp;
 409   ptid_t current_ptid;
 410   struct frame_info *cur_frame;
 411   struct cleanup *old_chain;
 412   struct frame_id saved_frame_id;
 413   char *extra_info;
 414
 415   /* Backup current thread and selected frame.  */
 416   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 417   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 418
 419   prune_threads ();
 420   target_find_new_threads ();
 421   current_ptid = inferior_ptid;
 422   for (tp = thread_list; tp; tp = tp->next)
 423     {
 424       if (ptid_equal (tp->ptid, current_ptid))
 425         printf_filtered ("* ");
 426       else
 427         printf_filtered ("  ");
 428
 429       printf_filtered ("%d %s", tp->num, target_tid_to_str (tp->ptid));
 430
 431       extra_info = target_extra_thread_info (tp);
 432       if (extra_info)
 433         printf_filtered (" (%s)", extra_info);
 434       puts_filtered ("  ");
 435       /* That switch put us at the top of the stack (leaf frame).  */
 436       switch_to_thread (tp->ptid);
 437       print_stack_frame (get_selected_frame (NULL), 0, LOCATION);
 438     }
 439
 440   /* Restores the current thread and the frame selected before
 441      the "info threads" command.  */
 442   do_cleanups (old_chain);
 443
 444   /*  If case we were not able to find the original frame, print the
 445       new selected frame.  */
 446   if (frame_find_by_id (saved_frame_id) == NULL)
 447     {
 448       warning (_("Couldn't restore frame in current thread, at frame 0"));
 449       print_stack_frame (get_selected_frame (NULL), 0, LOCATION);
 450     }
 451 }
 452
 453 /* Switch from one thread to another. */
 454
 455 static void
 456 switch_to_thread (ptid_t ptid)
 457 {
 458   if (ptid_equal (ptid, inferior_ptid))
 459     return;
 460
 461   inferior_ptid = ptid;
 462   reinit_frame_cache ();
 463   registers_changed ();
 464   stop_pc = read_pc ();
 465 }
 466
 467 static void
 468 restore_current_thread (ptid_t ptid)
 469 {
 470   if (!ptid_equal (ptid, inferior_ptid))
 471     {
 472       switch_to_thread (ptid);
 473     }
 474 }
 475
 476 static void
 477 restore_selected_frame (struct frame_id a_frame_id)
 478 {
 479   struct frame_info *selected_frame_info = NULL;
 480
 481   if (frame_id_eq (a_frame_id, null_frame_id))
 482     return;
 483
 484   if ((selected_frame_info = frame_find_by_id (a_frame_id)) != NULL)
 485     {
 486       select_frame (selected_frame_info);
 487     }
 488 }
 489
 490 struct current_thread_cleanup
 491 {
 492   ptid_t inferior_ptid;
 493   struct frame_id selected_frame_id;
 494 };
 495
 496 static void
 497 do_restore_current_thread_cleanup (void *arg)
 498 {
 499   struct current_thread_cleanup *old = arg;
 500   restore_current_thread (old->inferior_ptid);
 501   restore_selected_frame (old->selected_frame_id);
 502   xfree (old);
 503 }
 504
 505 static struct cleanup *
 506 make_cleanup_restore_current_thread (ptid_t inferior_ptid,
 507                                      struct frame_id a_frame_id)
 508 {
 509   struct current_thread_cleanup *old
 510     = xmalloc (sizeof (struct current_thread_cleanup));
 511   old->inferior_ptid = inferior_ptid;
 512   old->selected_frame_id = a_frame_id;
 513   return make_cleanup (do_restore_current_thread_cleanup, old);
 514 }
 515
 516 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 517    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 518    of two numbers seperated by a hyphen.  Examples:
 519
 520    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 521    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 522    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 523  */
 524
 525 static void
 526 thread_apply_all_command (char *cmd, int from_tty)
 527 {
 528   struct thread_info *tp;
 529   struct cleanup *old_chain;
 530   struct cleanup *saved_cmd_cleanup_chain;
 531   char *saved_cmd;
 532   struct frame_id saved_frame_id;
 533   ptid_t current_ptid;
 534   int thread_has_changed = 0;
 535
 536   if (cmd == NULL || *cmd == '\000')
 537     error (_("Please specify a command following the thread ID list"));
 538
 539   current_ptid = inferior_ptid;
 540   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 541   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 542
 543   /* It is safe to update the thread list now, before
 544      traversing it for "thread apply all".  MVS */
 545   target_find_new_threads ();
 546
 547   /* Save a copy of the command in case it is clobbered by
 548      execute_command */
 549   saved_cmd = xstrdup (cmd);
 550   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 551   for (tp = thread_list; tp; tp = tp->next)
 552     if (thread_alive (tp))
 553       {
 554         switch_to_thread (tp->ptid);
 555         printf_filtered (_("\nThread %d (%s):\n"),
 556                          tp->num, target_tid_to_str (inferior_ptid));
 557         execute_command (cmd, from_tty);
 558         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 559       }
 560
 561   if (!ptid_equal (current_ptid, inferior_ptid))
 562     thread_has_changed = 1;
 563
 564   do_cleanups (saved_cmd_cleanup_chain);
 565   do_cleanups (old_chain);
 566   /* Print stack frame only if we changed thread.  */
 567   if (thread_has_changed)
 568     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 569
 570 }
 571
 572 static void
 573 thread_apply_command (char *tidlist, int from_tty)
 574 {
 575   char *cmd;
 576   char *p;
 577   struct cleanup *old_chain;
 578   struct cleanup *saved_cmd_cleanup_chain;
 579   char *saved_cmd;
 580   struct frame_id saved_frame_id;
 581   ptid_t current_ptid;
 582   int thread_has_changed = 0;
 583
 584   if (tidlist == NULL || *tidlist == '\000')
 585     error (_("Please specify a thread ID list"));
 586
 587   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 588
 589   if (*cmd == '\000')
 590     error (_("Please specify a command following the thread ID list"));
 591
 592   current_ptid = inferior_ptid;
 593   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 594   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 595
 596   /* Save a copy of the command in case it is clobbered by
 597      execute_command */
 598   saved_cmd = xstrdup (cmd);
 599   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 600   while (tidlist < cmd)
 601     {
 602       struct thread_info *tp;
 603       int start, end;
 604
 605       start = strtol (tidlist, &p, 10);
 606       if (p == tidlist)
 607         error (_("Error parsing %s"), tidlist);
 608       tidlist = p;
 609
 610       while (*tidlist == ' ' || *tidlist == '\t')
 611         tidlist++;
 612
 613       if (*tidlist == '-')      /* Got a range of IDs? */
 614         {
 615           tidlist++;            /* Skip the - */
 616           end = strtol (tidlist, &p, 10);
 617           if (p == tidlist)
 618             error (_("Error parsing %s"), tidlist);
 619           tidlist = p;
 620
 621           while (*tidlist == ' ' || *tidlist == '\t')
 622             tidlist++;
 623         }
 624       else
 625         end = start;
 626
 627       for (; start <= end; start++)
 628         {
 629           tp = find_thread_id (start);
 630
 631           if (!tp)
 632             warning (_("Unknown thread %d."), start);
 633           else if (!thread_alive (tp))
 634             warning (_("Thread %d has terminated."), start);
 635           else
 636             {
 637               switch_to_thread (tp->ptid);
 638               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 639                                target_tid_to_str (inferior_ptid));
 640               execute_command (cmd, from_tty);
 641               strcpy (cmd, saved_cmd);  /* Restore exact command used previously */
 642             }
 643         }
 644     }
 645
 646   if (!ptid_equal (current_ptid, inferior_ptid))
 647     thread_has_changed = 1;
 648
 649   do_cleanups (saved_cmd_cleanup_chain);
 650   do_cleanups (old_chain);
 651   /* Print stack frame only if we changed thread.  */
 652   if (thread_has_changed)
 653     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 654 }
 655
 656 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 657    if prefix of arg is `apply'.  */
 658
 659 static void
 660 thread_command (char *tidstr, int from_tty)
 661 {
 662   if (!tidstr)
 663     {
 664       /* Don't generate an error, just say which thread is current. */
 665       if (target_has_stack)
 666         printf_filtered (_("[Current thread is %d (%s)]\n"),
 667                          pid_to_thread_id (inferior_ptid),
 668                          target_tid_to_str (inferior_ptid));
 669       else
 670         error (_("No stack."));
 671       return;
 672     }
 673
 674   gdb_thread_select (uiout, tidstr, NULL);
 675 }
 676
 677 static int
 678 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
 679 {
 680   int num;
 681   struct thread_info *tp;
 682
 683   num = value_as_long (parse_and_eval (tidstr));
 684
 685   tp = find_thread_id (num);
 686
 687   if (!tp)
 688     error (_("Thread ID %d not known."), num);
 689
 690   if (!thread_alive (tp))
 691     error (_("Thread ID %d has terminated."), num);
 692
 693   switch_to_thread (tp->ptid);
 694
 695   ui_out_text (uiout, "[Switching to thread ");
 696   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
 697   ui_out_text (uiout, " (");
 698   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
 699   ui_out_text (uiout, ")]");
 700
 701   print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 702   return GDB_RC_OK;
 703 }
 704
 705 enum gdb_rc
 706 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
 707 {
 708   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
 709                                  error_message, RETURN_MASK_ALL) < 0)
 710     return GDB_RC_FAIL;
 711   return GDB_RC_OK;
 712 }
 713
 714 /* Commands with a prefix of `thread'.  */
 715 struct cmd_list_element *thread_cmd_list = NULL;
 716
 717 void
 718 _initialize_thread (void)
 719 {
 720   static struct cmd_list_element *thread_apply_list = NULL;
 721
 722   add_info ("threads", info_threads_command,
 723             _("IDs of currently known threads."));
 724
 725   add_prefix_cmd ("thread", class_run, thread_command, _("\
 726 Use this command to switch between threads.\n\
 727 The new thread ID must be currently known."),
 728                   &thread_cmd_list, "thread ", 1, &cmdlist);
 729
 730   add_prefix_cmd ("apply", class_run, thread_apply_command,
 731                   _("Apply a command to a list of threads."),
 732                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 733
 734   add_cmd ("all", class_run, thread_apply_all_command,
 735            _("Apply a command to all threads."), &thread_apply_list);
 736
 737   if (!xdb_commands)
 738     add_com_alias ("t", "thread", class_run, 1);
 739 }