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 2 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, write to the Free Software
  22    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23    Boston, MA 02110-1301, USA.  */
  24
  25 #include "defs.h"
  26 #include "symtab.h"
  27 #include "frame.h"
  28 #include "inferior.h"
  29 #include "environ.h"
  30 #include "value.h"
  31 #include "target.h"
  32 #include "gdbthread.h"
  33 #include "exceptions.h"
  34 #include "command.h"
  35 #include "gdbcmd.h"
  36 #include "regcache.h"
  37 #include "gdb.h"
  38 #include "gdb_string.h"
  39
  40 #include <ctype.h>
  41 #include <sys/types.h>
  42 #include <signal.h>
  43 #include "ui-out.h"
  44
  45 /* Definition of struct thread_info exported to gdbthread.h */
  46
  47 /* Prototypes for exported functions. */
  48
  49 void _initialize_thread (void);
  50
  51 /* Prototypes for local functions. */
  52
  53 static struct thread_info *thread_list = NULL;
  54 static int highest_thread_num;
  55
  56 static struct thread_info *find_thread_id (int num);
  57
  58 static void thread_command (char *tidstr, int from_tty);
  59 static void thread_apply_all_command (char *, int);
  60 static int thread_alive (struct thread_info *);
  61 static void info_threads_command (char *, int);
  62 static void thread_apply_command (char *, int);
  63 static void restore_current_thread (ptid_t);
  64 static void switch_to_thread (ptid_t ptid);
  65 static void prune_threads (void);
  66 static struct cleanup *make_cleanup_restore_current_thread (ptid_t,
  67                                                             struct frame_id);
  68
  69 void
  70 delete_step_resume_breakpoint (void *arg)
  71 {
  72   struct breakpoint **breakpointp = (struct breakpoint **) arg;
  73   struct thread_info *tp;
  74
  75   if (*breakpointp != NULL)
  76     {
  77       delete_breakpoint (*breakpointp);
  78       for (tp = thread_list; tp; tp = tp->next)
  79         if (tp->step_resume_breakpoint == *breakpointp)
  80           tp->step_resume_breakpoint = NULL;
  81
  82       *breakpointp = NULL;
  83     }
  84 }
  85
  86 static void
  87 free_thread (struct thread_info *tp)
  88 {
  89   /* NOTE: this will take care of any left-over step_resume breakpoints,
  90      but not any user-specified thread-specific breakpoints. */
  91   if (tp->step_resume_breakpoint)
  92     delete_breakpoint (tp->step_resume_breakpoint);
  93
  94   /* FIXME: do I ever need to call the back-end to give it a
  95      chance at this private data before deleting the thread?  */
  96   if (tp->private)
  97     xfree (tp->private);
  98
  99   xfree (tp);
 100 }
 101
 102 void
 103 init_thread_list (void)
 104 {
 105   struct thread_info *tp, *tpnext;
 106
 107   highest_thread_num = 0;
 108   if (!thread_list)
 109     return;
 110
 111   for (tp = thread_list; tp; tp = tpnext)
 112     {
 113       tpnext = tp->next;
 114       free_thread (tp);
 115     }
 116
 117   thread_list = NULL;
 118 }
 119
 120 /* add_thread now returns a pointer to the new thread_info,
 121    so that back_ends can initialize their private data.  */
 122
 123 struct thread_info *
 124 add_thread (ptid_t ptid)
 125 {
 126   struct thread_info *tp;
 127
 128   tp = (struct thread_info *) xmalloc (sizeof (*tp));
 129   memset (tp, 0, sizeof (*tp));
 130   tp->ptid = ptid;
 131   tp->num = ++highest_thread_num;
 132   tp->next = thread_list;
 133   thread_list = tp;
 134   return tp;
 135 }
 136
 137 void
 138 delete_thread (ptid_t ptid)
 139 {
 140   struct thread_info *tp, *tpprev;
 141
 142   tpprev = NULL;
 143
 144   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 145     if (ptid_equal (tp->ptid, ptid))
 146       break;
 147
 148   if (!tp)
 149     return;
 150
 151   if (tpprev)
 152     tpprev->next = tp->next;
 153   else
 154     thread_list = tp->next;
 155
 156   free_thread (tp);
 157 }
 158
 159 static struct thread_info *
 160 find_thread_id (int num)
 161 {
 162   struct thread_info *tp;
 163
 164   for (tp = thread_list; tp; tp = tp->next)
 165     if (tp->num == num)
 166       return tp;
 167
 168   return NULL;
 169 }
 170
 171 /* Find a thread_info by matching PTID.  */
 172 struct thread_info *
 173 find_thread_pid (ptid_t ptid)
 174 {
 175   struct thread_info *tp;
 176
 177   for (tp = thread_list; tp; tp = tp->next)
 178     if (ptid_equal (tp->ptid, ptid))
 179       return tp;
 180
 181   return NULL;
 182 }
 183
 184 /*
 185  * Thread iterator function.
 186  *
 187  * Calls a callback function once for each thread, so long as
 188  * the callback function returns false.  If the callback function
 189  * returns true, the iteration will end and the current thread
 190  * will be returned.  This can be useful for implementing a
 191  * search for a thread with arbitrary attributes, or for applying
 192  * some operation to every thread.
 193  *
 194  * FIXME: some of the existing functionality, such as
 195  * "Thread apply all", might be rewritten using this functionality.
 196  */
 197
 198 struct thread_info *
 199 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 200                       void *data)
 201 {
 202   struct thread_info *tp;
 203
 204   for (tp = thread_list; tp; tp = tp->next)
 205     if ((*callback) (tp, data))
 206       return tp;
 207
 208   return NULL;
 209 }
 210
 211 int
 212 valid_thread_id (int num)
 213 {
 214   struct thread_info *tp;
 215
 216   for (tp = thread_list; tp; tp = tp->next)
 217     if (tp->num == num)
 218       return 1;
 219
 220   return 0;
 221 }
 222
 223 int
 224 pid_to_thread_id (ptid_t ptid)
 225 {
 226   struct thread_info *tp;
 227
 228   for (tp = thread_list; tp; tp = tp->next)
 229     if (ptid_equal (tp->ptid, ptid))
 230       return tp->num;
 231
 232   return 0;
 233 }
 234
 235 ptid_t
 236 thread_id_to_pid (int num)
 237 {
 238   struct thread_info *thread = find_thread_id (num);
 239   if (thread)
 240     return thread->ptid;
 241   else
 242     return pid_to_ptid (-1);
 243 }
 244
 245 int
 246 in_thread_list (ptid_t ptid)
 247 {
 248   struct thread_info *tp;
 249
 250   for (tp = thread_list; tp; tp = tp->next)
 251     if (ptid_equal (tp->ptid, ptid))
 252       return 1;
 253
 254   return 0;                     /* Never heard of 'im */
 255 }
 256
 257 /* Print a list of thread ids currently known, and the total number of
 258    threads. To be used from within catch_errors. */
 259 static int
 260 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 261 {
 262   struct thread_info *tp;
 263   int num = 0;
 264   struct cleanup *cleanup_chain;
 265
 266   prune_threads ();
 267   target_find_new_threads ();
 268
 269   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 270
 271   for (tp = thread_list; tp; tp = tp->next)
 272     {
 273       num++;
 274       ui_out_field_int (uiout, "thread-id", tp->num);
 275     }
 276
 277   do_cleanups (cleanup_chain);
 278   ui_out_field_int (uiout, "number-of-threads", num);
 279   return GDB_RC_OK;
 280 }
 281
 282 /* Official gdblib interface function to get a list of thread ids and
 283    the total number. */
 284 enum gdb_rc
 285 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 286 {
 287   if (catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 288                                  error_message, RETURN_MASK_ALL) < 0)
 289     return GDB_RC_FAIL;
 290   return GDB_RC_OK;
 291 }
 292
 293 /* Load infrun state for the thread PID.  */
 294
 295 void
 296 load_infrun_state (ptid_t ptid,
 297                    CORE_ADDR *prev_pc,
 298                    int *trap_expected,
 299                    struct breakpoint **step_resume_breakpoint,
 300                    CORE_ADDR *step_range_start,
 301                    CORE_ADDR *step_range_end,
 302                    struct frame_id *step_frame_id,
 303                    int *handling_longjmp,
 304                    int *another_trap,
 305                    int *stepping_through_solib_after_catch,
 306                    bpstat *stepping_through_solib_catchpoints,
 307                    int *current_line,
 308                    struct symtab **current_symtab)
 309 {
 310   struct thread_info *tp;
 311
 312   /* If we can't find the thread, then we're debugging a single threaded
 313      process.  No need to do anything in that case.  */
 314   tp = find_thread_id (pid_to_thread_id (ptid));
 315   if (tp == NULL)
 316     return;
 317
 318   *prev_pc = tp->prev_pc;
 319   *trap_expected = tp->trap_expected;
 320   *step_resume_breakpoint = tp->step_resume_breakpoint;
 321   *step_range_start = tp->step_range_start;
 322   *step_range_end = tp->step_range_end;
 323   *step_frame_id = tp->step_frame_id;
 324   *handling_longjmp = tp->handling_longjmp;
 325   *another_trap = tp->another_trap;
 326   *stepping_through_solib_after_catch =
 327     tp->stepping_through_solib_after_catch;
 328   *stepping_through_solib_catchpoints =
 329     tp->stepping_through_solib_catchpoints;
 330   *current_line = tp->current_line;
 331   *current_symtab = tp->current_symtab;
 332 }
 333
 334 /* Save infrun state for the thread PID.  */
 335
 336 void
 337 save_infrun_state (ptid_t ptid,
 338                    CORE_ADDR prev_pc,
 339                    int trap_expected,
 340                    struct breakpoint *step_resume_breakpoint,
 341                    CORE_ADDR step_range_start,
 342                    CORE_ADDR step_range_end,
 343                    const struct frame_id *step_frame_id,
 344                    int handling_longjmp,
 345                    int another_trap,
 346                    int stepping_through_solib_after_catch,
 347                    bpstat stepping_through_solib_catchpoints,
 348                    int current_line,
 349                    struct symtab *current_symtab)
 350 {
 351   struct thread_info *tp;
 352
 353   /* If we can't find the thread, then we're debugging a single-threaded
 354      process.  Nothing to do in that case.  */
 355   tp = find_thread_id (pid_to_thread_id (ptid));
 356   if (tp == NULL)
 357     return;
 358
 359   tp->prev_pc = prev_pc;
 360   tp->trap_expected = trap_expected;
 361   tp->step_resume_breakpoint = step_resume_breakpoint;
 362   tp->step_range_start = step_range_start;
 363   tp->step_range_end = step_range_end;
 364   tp->step_frame_id = (*step_frame_id);
 365   tp->handling_longjmp = handling_longjmp;
 366   tp->another_trap = another_trap;
 367   tp->stepping_through_solib_after_catch = stepping_through_solib_after_catch;
 368   tp->stepping_through_solib_catchpoints = stepping_through_solib_catchpoints;
 369   tp->current_line = current_line;
 370   tp->current_symtab = current_symtab;
 371 }
 372
 373 /* Return true if TP is an active thread. */
 374 static int
 375 thread_alive (struct thread_info *tp)
 376 {
 377   if (PIDGET (tp->ptid) == -1)
 378     return 0;
 379   if (!target_thread_alive (tp->ptid))
 380     {
 381       tp->ptid = pid_to_ptid (-1);      /* Mark it as dead */
 382       return 0;
 383     }
 384   return 1;
 385 }
 386
 387 static void
 388 prune_threads (void)
 389 {
 390   struct thread_info *tp, *next;
 391
 392   for (tp = thread_list; tp; tp = next)
 393     {
 394       next = tp->next;
 395       if (!thread_alive (tp))
 396         delete_thread (tp->ptid);
 397     }
 398 }
 399
 400 /* Print information about currently known threads
 401
 402  * Note: this has the drawback that it _really_ switches
 403  *       threads, which frees the frame cache.  A no-side
 404  *       effects info-threads command would be nicer.
 405  */
 406
 407 static void
 408 info_threads_command (char *arg, int from_tty)
 409 {
 410   struct thread_info *tp;
 411   ptid_t current_ptid;
 412   struct frame_info *cur_frame;
 413   struct cleanup *old_chain;
 414   struct frame_id saved_frame_id;
 415   char *extra_info;
 416
 417   /* Backup current thread and selected frame.  */
 418   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 419   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 420
 421   prune_threads ();
 422   target_find_new_threads ();
 423   current_ptid = inferior_ptid;
 424   for (tp = thread_list; tp; tp = tp->next)
 425     {
 426       if (ptid_equal (tp->ptid, current_ptid))
 427         printf_filtered ("* ");
 428       else
 429         printf_filtered ("  ");
 430
 431       printf_filtered ("%d %s", tp->num, target_tid_to_str (tp->ptid));
 432
 433       extra_info = target_extra_thread_info (tp);
 434       if (extra_info)
 435         printf_filtered (" (%s)", extra_info);
 436       puts_filtered ("  ");
 437       /* That switch put us at the top of the stack (leaf frame).  */
 438       switch_to_thread (tp->ptid);
 439       print_stack_frame (get_selected_frame (NULL), 0, LOCATION);
 440     }
 441
 442   /* Restores the current thread and the frame selected before
 443      the "info threads" command.  */
 444   do_cleanups (old_chain);
 445
 446   /*  If case we were not able to find the original frame, print the
 447       new selected frame.  */
 448   if (frame_find_by_id (saved_frame_id) == NULL)
 449     {
 450       warning (_("Couldn't restore frame in current thread, at frame 0"));
 451       print_stack_frame (get_selected_frame (NULL), 0, LOCATION);
 452     }
 453 }
 454
 455 /* Switch from one thread to another. */
 456
 457 static void
 458 switch_to_thread (ptid_t ptid)
 459 {
 460   if (ptid_equal (ptid, inferior_ptid))
 461     return;
 462
 463   inferior_ptid = ptid;
 464   reinit_frame_cache ();
 465   registers_changed ();
 466   stop_pc = read_pc ();
 467 }
 468
 469 static void
 470 restore_current_thread (ptid_t ptid)
 471 {
 472   if (!ptid_equal (ptid, inferior_ptid))
 473     {
 474       switch_to_thread (ptid);
 475     }
 476 }
 477
 478 static void
 479 restore_selected_frame (struct frame_id a_frame_id)
 480 {
 481   struct frame_info *selected_frame_info = NULL;
 482
 483   if (frame_id_eq (a_frame_id, null_frame_id))
 484     return;
 485
 486   if ((selected_frame_info = frame_find_by_id (a_frame_id)) != NULL)
 487     {
 488       select_frame (selected_frame_info);
 489     }
 490 }
 491
 492 struct current_thread_cleanup
 493 {
 494   ptid_t inferior_ptid;
 495   struct frame_id selected_frame_id;
 496 };
 497
 498 static void
 499 do_restore_current_thread_cleanup (void *arg)
 500 {
 501   struct current_thread_cleanup *old = arg;
 502   restore_current_thread (old->inferior_ptid);
 503   restore_selected_frame (old->selected_frame_id);
 504   xfree (old);
 505 }
 506
 507 static struct cleanup *
 508 make_cleanup_restore_current_thread (ptid_t inferior_ptid,
 509                                      struct frame_id a_frame_id)
 510 {
 511   struct current_thread_cleanup *old
 512     = xmalloc (sizeof (struct current_thread_cleanup));
 513   old->inferior_ptid = inferior_ptid;
 514   old->selected_frame_id = a_frame_id;
 515   return make_cleanup (do_restore_current_thread_cleanup, old);
 516 }
 517
 518 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 519    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 520    of two numbers seperated by a hyphen.  Examples:
 521
 522    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 523    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 524    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 525  */
 526
 527 static void
 528 thread_apply_all_command (char *cmd, int from_tty)
 529 {
 530   struct thread_info *tp;
 531   struct cleanup *old_chain;
 532   struct cleanup *saved_cmd_cleanup_chain;
 533   char *saved_cmd;
 534   struct frame_id saved_frame_id;
 535   ptid_t current_ptid;
 536   int thread_has_changed = 0;
 537
 538   if (cmd == NULL || *cmd == '\000')
 539     error (_("Please specify a command following the thread ID list"));
 540
 541   current_ptid = inferior_ptid;
 542   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 543   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 544
 545   /* It is safe to update the thread list now, before
 546      traversing it for "thread apply all".  MVS */
 547   target_find_new_threads ();
 548
 549   /* Save a copy of the command in case it is clobbered by
 550      execute_command */
 551   saved_cmd = xstrdup (cmd);
 552   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 553   for (tp = thread_list; tp; tp = tp->next)
 554     if (thread_alive (tp))
 555       {
 556         switch_to_thread (tp->ptid);
 557         printf_filtered (_("\nThread %d (%s):\n"),
 558                          tp->num, target_tid_to_str (inferior_ptid));
 559         execute_command (cmd, from_tty);
 560         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 561       }
 562
 563   if (!ptid_equal (current_ptid, inferior_ptid))
 564     thread_has_changed = 1;
 565
 566   do_cleanups (saved_cmd_cleanup_chain);
 567   do_cleanups (old_chain);
 568   /* Print stack frame only if we changed thread.  */
 569   if (thread_has_changed)
 570     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 571
 572 }
 573
 574 static void
 575 thread_apply_command (char *tidlist, int from_tty)
 576 {
 577   char *cmd;
 578   char *p;
 579   struct cleanup *old_chain;
 580   struct cleanup *saved_cmd_cleanup_chain;
 581   char *saved_cmd;
 582   struct frame_id saved_frame_id;
 583   ptid_t current_ptid;
 584   int thread_has_changed = 0;
 585
 586   if (tidlist == NULL || *tidlist == '\000')
 587     error (_("Please specify a thread ID list"));
 588
 589   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 590
 591   if (*cmd == '\000')
 592     error (_("Please specify a command following the thread ID list"));
 593
 594   current_ptid = inferior_ptid;
 595   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 596   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 597
 598   /* Save a copy of the command in case it is clobbered by
 599      execute_command */
 600   saved_cmd = xstrdup (cmd);
 601   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 602   while (tidlist < cmd)
 603     {
 604       struct thread_info *tp;
 605       int start, end;
 606
 607       start = strtol (tidlist, &p, 10);
 608       if (p == tidlist)
 609         error (_("Error parsing %s"), tidlist);
 610       tidlist = p;
 611
 612       while (*tidlist == ' ' || *tidlist == '\t')
 613         tidlist++;
 614
 615       if (*tidlist == '-')      /* Got a range of IDs? */
 616         {
 617           tidlist++;            /* Skip the - */
 618           end = strtol (tidlist, &p, 10);
 619           if (p == tidlist)
 620             error (_("Error parsing %s"), tidlist);
 621           tidlist = p;
 622
 623           while (*tidlist == ' ' || *tidlist == '\t')
 624             tidlist++;
 625         }
 626       else
 627         end = start;
 628
 629       for (; start <= end; start++)
 630         {
 631           tp = find_thread_id (start);
 632
 633           if (!tp)
 634             warning (_("Unknown thread %d."), start);
 635           else if (!thread_alive (tp))
 636             warning (_("Thread %d has terminated."), start);
 637           else
 638             {
 639               switch_to_thread (tp->ptid);
 640               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 641                                target_tid_to_str (inferior_ptid));
 642               execute_command (cmd, from_tty);
 643               strcpy (cmd, saved_cmd);  /* Restore exact command used previously */
 644             }
 645         }
 646     }
 647
 648   if (!ptid_equal (current_ptid, inferior_ptid))
 649     thread_has_changed = 1;
 650
 651   do_cleanups (saved_cmd_cleanup_chain);
 652   do_cleanups (old_chain);
 653   /* Print stack frame only if we changed thread.  */
 654   if (thread_has_changed)
 655     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 656 }
 657
 658 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 659    if prefix of arg is `apply'.  */
 660
 661 static void
 662 thread_command (char *tidstr, int from_tty)
 663 {
 664   if (!tidstr)
 665     {
 666       /* Don't generate an error, just say which thread is current. */
 667       if (target_has_stack)
 668         printf_filtered (_("[Current thread is %d (%s)]\n"),
 669                          pid_to_thread_id (inferior_ptid),
 670                          target_tid_to_str (inferior_ptid));
 671       else
 672         error (_("No stack."));
 673       return;
 674     }
 675
 676   gdb_thread_select (uiout, tidstr, NULL);
 677 }
 678
 679 static int
 680 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
 681 {
 682   int num;
 683   struct thread_info *tp;
 684
 685   num = value_as_long (parse_and_eval (tidstr));
 686
 687   tp = find_thread_id (num);
 688
 689   if (!tp)
 690     error (_("Thread ID %d not known."), num);
 691
 692   if (!thread_alive (tp))
 693     error (_("Thread ID %d has terminated."), num);
 694
 695   switch_to_thread (tp->ptid);
 696
 697   ui_out_text (uiout, "[Switching to thread ");
 698   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
 699   ui_out_text (uiout, " (");
 700   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
 701   ui_out_text (uiout, ")]");
 702
 703   print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 704   return GDB_RC_OK;
 705 }
 706
 707 enum gdb_rc
 708 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
 709 {
 710   if (catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
 711                                  error_message, RETURN_MASK_ALL) < 0)
 712     return GDB_RC_FAIL;
 713   return GDB_RC_OK;
 714 }
 715
 716 /* Commands with a prefix of `thread'.  */
 717 struct cmd_list_element *thread_cmd_list = NULL;
 718
 719 void
 720 _initialize_thread (void)
 721 {
 722   static struct cmd_list_element *thread_apply_list = NULL;
 723
 724   add_info ("threads", info_threads_command,
 725             _("IDs of currently known threads."));
 726
 727   add_prefix_cmd ("thread", class_run, thread_command, _("\
 728 Use this command to switch between threads.\n\
 729 The new thread ID must be currently known."),
 730                   &thread_cmd_list, "thread ", 1, &cmdlist);
 731
 732   add_prefix_cmd ("apply", class_run, thread_apply_command,
 733                   _("Apply a command to a list of threads."),
 734                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 735
 736   add_cmd ("all", class_run, thread_apply_all_command,
 737            _("Apply a command to all threads."), &thread_apply_list);
 738
 739   if (!xdb_commands)
 740     add_com_alias ("t", "thread", class_run, 1);
 741 }