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 /*#include "lynxos-core.h" */
  46
  47 /* Definition of struct thread_info exported to gdbthread.h */
  48
  49 /* Prototypes for exported functions. */
  50
  51 void _initialize_thread (void);
  52
  53 /* Prototypes for local functions. */
  54
  55 static struct thread_info *thread_list = NULL;
  56 static int highest_thread_num;
  57
  58 static struct thread_info *find_thread_id (int num);
  59
  60 static void thread_command (char *tidstr, int from_tty);
  61 static void thread_apply_all_command (char *, int);
  62 static int thread_alive (struct thread_info *);
  63 static void info_threads_command (char *, int);
  64 static void thread_apply_command (char *, int);
  65 static void restore_current_thread (ptid_t);
  66 static void switch_to_thread (ptid_t ptid);
  67 static void prune_threads (void);
  68 static struct cleanup *make_cleanup_restore_current_thread (ptid_t,
  69                                                             struct frame_id);
  70
  71 void
  72 delete_step_resume_breakpoint (void *arg)
  73 {
  74   struct breakpoint **breakpointp = (struct breakpoint **) arg;
  75   struct thread_info *tp;
  76
  77   if (*breakpointp != NULL)
  78     {
  79       delete_breakpoint (*breakpointp);
  80       for (tp = thread_list; tp; tp = tp->next)
  81         if (tp->step_resume_breakpoint == *breakpointp)
  82           tp->step_resume_breakpoint = NULL;
  83
  84       *breakpointp = NULL;
  85     }
  86 }
  87
  88 static void
  89 free_thread (struct thread_info *tp)
  90 {
  91   /* NOTE: this will take care of any left-over step_resume breakpoints,
  92      but not any user-specified thread-specific breakpoints. */
  93   if (tp->step_resume_breakpoint)
  94     delete_breakpoint (tp->step_resume_breakpoint);
  95
  96   /* FIXME: do I ever need to call the back-end to give it a
  97      chance at this private data before deleting the thread?  */
  98   if (tp->private)
  99     xfree (tp->private);
 100
 101   xfree (tp);
 102 }
 103
 104 void
 105 init_thread_list (void)
 106 {
 107   struct thread_info *tp, *tpnext;
 108
 109   highest_thread_num = 0;
 110   if (!thread_list)
 111     return;
 112
 113   for (tp = thread_list; tp; tp = tpnext)
 114     {
 115       tpnext = tp->next;
 116       free_thread (tp);
 117     }
 118
 119   thread_list = NULL;
 120 }
 121
 122 /* add_thread now returns a pointer to the new thread_info,
 123    so that back_ends can initialize their private data.  */
 124
 125 struct thread_info *
 126 add_thread (ptid_t ptid)
 127 {
 128   struct thread_info *tp;
 129
 130   tp = (struct thread_info *) xmalloc (sizeof (*tp));
 131   memset (tp, 0, sizeof (*tp));
 132   tp->ptid = ptid;
 133   tp->num = ++highest_thread_num;
 134   tp->next = thread_list;
 135   thread_list = tp;
 136   return tp;
 137 }
 138
 139 void
 140 delete_thread (ptid_t ptid)
 141 {
 142   struct thread_info *tp, *tpprev;
 143
 144   tpprev = NULL;
 145
 146   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 147     if (ptid_equal (tp->ptid, ptid))
 148       break;
 149
 150   if (!tp)
 151     return;
 152
 153   if (tpprev)
 154     tpprev->next = tp->next;
 155   else
 156     thread_list = tp->next;
 157
 158   free_thread (tp);
 159 }
 160
 161 static struct thread_info *
 162 find_thread_id (int num)
 163 {
 164   struct thread_info *tp;
 165
 166   for (tp = thread_list; tp; tp = tp->next)
 167     if (tp->num == num)
 168       return tp;
 169
 170   return NULL;
 171 }
 172
 173 /* Find a thread_info by matching PTID.  */
 174 struct thread_info *
 175 find_thread_pid (ptid_t ptid)
 176 {
 177   struct thread_info *tp;
 178
 179   for (tp = thread_list; tp; tp = tp->next)
 180     if (ptid_equal (tp->ptid, ptid))
 181       return tp;
 182
 183   return NULL;
 184 }
 185
 186 /*
 187  * Thread iterator function.
 188  *
 189  * Calls a callback function once for each thread, so long as
 190  * the callback function returns false.  If the callback function
 191  * returns true, the iteration will end and the current thread
 192  * will be returned.  This can be useful for implementing a
 193  * search for a thread with arbitrary attributes, or for applying
 194  * some operation to every thread.
 195  *
 196  * FIXME: some of the existing functionality, such as
 197  * "Thread apply all", might be rewritten using this functionality.
 198  */
 199
 200 struct thread_info *
 201 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 202                       void *data)
 203 {
 204   struct thread_info *tp;
 205
 206   for (tp = thread_list; tp; tp = tp->next)
 207     if ((*callback) (tp, data))
 208       return tp;
 209
 210   return NULL;
 211 }
 212
 213 int
 214 valid_thread_id (int num)
 215 {
 216   struct thread_info *tp;
 217
 218   for (tp = thread_list; tp; tp = tp->next)
 219     if (tp->num == num)
 220       return 1;
 221
 222   return 0;
 223 }
 224
 225 int
 226 pid_to_thread_id (ptid_t ptid)
 227 {
 228   struct thread_info *tp;
 229
 230   for (tp = thread_list; tp; tp = tp->next)
 231     if (ptid_equal (tp->ptid, ptid))
 232       return tp->num;
 233
 234   return 0;
 235 }
 236
 237 ptid_t
 238 thread_id_to_pid (int num)
 239 {
 240   struct thread_info *thread = find_thread_id (num);
 241   if (thread)
 242     return thread->ptid;
 243   else
 244     return pid_to_ptid (-1);
 245 }
 246
 247 int
 248 in_thread_list (ptid_t ptid)
 249 {
 250   struct thread_info *tp;
 251
 252   for (tp = thread_list; tp; tp = tp->next)
 253     if (ptid_equal (tp->ptid, ptid))
 254       return 1;
 255
 256   return 0;                     /* Never heard of 'im */
 257 }
 258
 259 /* Print a list of thread ids currently known, and the total number of
 260    threads. To be used from within catch_errors. */
 261 static int
 262 do_captured_list_thread_ids (struct ui_out *uiout, void *arg)
 263 {
 264   struct thread_info *tp;
 265   int num = 0;
 266   struct cleanup *cleanup_chain;
 267
 268   prune_threads ();
 269   target_find_new_threads ();
 270
 271   cleanup_chain = make_cleanup_ui_out_tuple_begin_end (uiout, "thread-ids");
 272
 273   for (tp = thread_list; tp; tp = tp->next)
 274     {
 275       num++;
 276       ui_out_field_int (uiout, "thread-id", tp->num);
 277     }
 278
 279   do_cleanups (cleanup_chain);
 280   ui_out_field_int (uiout, "number-of-threads", num);
 281   return GDB_RC_OK;
 282 }
 283
 284 /* Official gdblib interface function to get a list of thread ids and
 285    the total number. */
 286 enum gdb_rc
 287 gdb_list_thread_ids (struct ui_out *uiout, char **error_message)
 288 {
 289   return catch_exceptions_with_msg (uiout, do_captured_list_thread_ids, NULL,
 290                                     error_message, RETURN_MASK_ALL);
 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   flush_cached_frames ();
 465   registers_changed ();
 466   stop_pc = read_pc ();
 467   select_frame (get_current_frame ());
 468 }
 469
 470 static void
 471 restore_current_thread (ptid_t ptid)
 472 {
 473   if (!ptid_equal (ptid, inferior_ptid))
 474     {
 475       switch_to_thread (ptid);
 476     }
 477 }
 478
 479 static void
 480 restore_selected_frame (struct frame_id a_frame_id)
 481 {
 482   struct frame_info *selected_frame_info = NULL;
 483
 484   if (frame_id_eq (a_frame_id, null_frame_id))
 485     return;
 486
 487   if ((selected_frame_info = frame_find_by_id (a_frame_id)) != NULL)
 488     {
 489       select_frame (selected_frame_info);
 490     }
 491 }
 492
 493 struct current_thread_cleanup
 494 {
 495   ptid_t inferior_ptid;
 496   struct frame_id selected_frame_id;
 497 };
 498
 499 static void
 500 do_restore_current_thread_cleanup (void *arg)
 501 {
 502   struct current_thread_cleanup *old = arg;
 503   restore_current_thread (old->inferior_ptid);
 504   restore_selected_frame (old->selected_frame_id);
 505   xfree (old);
 506 }
 507
 508 static struct cleanup *
 509 make_cleanup_restore_current_thread (ptid_t inferior_ptid,
 510                                      struct frame_id a_frame_id)
 511 {
 512   struct current_thread_cleanup *old
 513     = xmalloc (sizeof (struct current_thread_cleanup));
 514   old->inferior_ptid = inferior_ptid;
 515   old->selected_frame_id = a_frame_id;
 516   return make_cleanup (do_restore_current_thread_cleanup, old);
 517 }
 518
 519 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 520    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 521    of two numbers seperated by a hyphen.  Examples:
 522
 523    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 524    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 525    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 526  */
 527
 528 static void
 529 thread_apply_all_command (char *cmd, int from_tty)
 530 {
 531   struct thread_info *tp;
 532   struct cleanup *old_chain;
 533   struct cleanup *saved_cmd_cleanup_chain;
 534   char *saved_cmd;
 535   struct frame_id saved_frame_id;
 536   ptid_t current_ptid;
 537   int thread_has_changed = 0;
 538
 539   if (cmd == NULL || *cmd == '\000')
 540     error (_("Please specify a command following the thread ID list"));
 541
 542   current_ptid = inferior_ptid;
 543   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 544   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 545
 546   /* It is safe to update the thread list now, before
 547      traversing it for "thread apply all".  MVS */
 548   target_find_new_threads ();
 549
 550   /* Save a copy of the command in case it is clobbered by
 551      execute_command */
 552   saved_cmd = xstrdup (cmd);
 553   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 554   for (tp = thread_list; tp; tp = tp->next)
 555     if (thread_alive (tp))
 556       {
 557         switch_to_thread (tp->ptid);
 558         printf_filtered (_("\nThread %d (%s):\n"),
 559                          tp->num, target_tid_to_str (inferior_ptid));
 560         execute_command (cmd, from_tty);
 561         strcpy (cmd, saved_cmd);        /* Restore exact command used previously */
 562       }
 563
 564   if (!ptid_equal (current_ptid, inferior_ptid))
 565     thread_has_changed = 1;
 566
 567   do_cleanups (saved_cmd_cleanup_chain);
 568   do_cleanups (old_chain);
 569   /* Print stack frame only if we changed thread.  */
 570   if (thread_has_changed)
 571     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 572
 573 }
 574
 575 static void
 576 thread_apply_command (char *tidlist, int from_tty)
 577 {
 578   char *cmd;
 579   char *p;
 580   struct cleanup *old_chain;
 581   struct cleanup *saved_cmd_cleanup_chain;
 582   char *saved_cmd;
 583   struct frame_id saved_frame_id;
 584   ptid_t current_ptid;
 585   int thread_has_changed = 0;
 586
 587   if (tidlist == NULL || *tidlist == '\000')
 588     error (_("Please specify a thread ID list"));
 589
 590   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 591
 592   if (*cmd == '\000')
 593     error (_("Please specify a command following the thread ID list"));
 594
 595   current_ptid = inferior_ptid;
 596   saved_frame_id = get_frame_id (get_selected_frame (NULL));
 597   old_chain = make_cleanup_restore_current_thread (inferior_ptid, saved_frame_id);
 598
 599   /* Save a copy of the command in case it is clobbered by
 600      execute_command */
 601   saved_cmd = xstrdup (cmd);
 602   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 603   while (tidlist < cmd)
 604     {
 605       struct thread_info *tp;
 606       int start, end;
 607
 608       start = strtol (tidlist, &p, 10);
 609       if (p == tidlist)
 610         error (_("Error parsing %s"), tidlist);
 611       tidlist = p;
 612
 613       while (*tidlist == ' ' || *tidlist == '\t')
 614         tidlist++;
 615
 616       if (*tidlist == '-')      /* Got a range of IDs? */
 617         {
 618           tidlist++;            /* Skip the - */
 619           end = strtol (tidlist, &p, 10);
 620           if (p == tidlist)
 621             error (_("Error parsing %s"), tidlist);
 622           tidlist = p;
 623
 624           while (*tidlist == ' ' || *tidlist == '\t')
 625             tidlist++;
 626         }
 627       else
 628         end = start;
 629
 630       for (; start <= end; start++)
 631         {
 632           tp = find_thread_id (start);
 633
 634           if (!tp)
 635             warning (_("Unknown thread %d."), start);
 636           else if (!thread_alive (tp))
 637             warning (_("Thread %d has terminated."), start);
 638           else
 639             {
 640               switch_to_thread (tp->ptid);
 641               printf_filtered (_("\nThread %d (%s):\n"), tp->num,
 642                                target_tid_to_str (inferior_ptid));
 643               execute_command (cmd, from_tty);
 644               strcpy (cmd, saved_cmd);  /* Restore exact command used previously */
 645             }
 646         }
 647     }
 648
 649   if (!ptid_equal (current_ptid, inferior_ptid))
 650     thread_has_changed = 1;
 651
 652   do_cleanups (saved_cmd_cleanup_chain);
 653   do_cleanups (old_chain);
 654   /* Print stack frame only if we changed thread.  */
 655   if (thread_has_changed)
 656     print_stack_frame (get_current_frame (), 1, SRC_LINE);
 657 }
 658
 659 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 660    if prefix of arg is `apply'.  */
 661
 662 static void
 663 thread_command (char *tidstr, int from_tty)
 664 {
 665   if (!tidstr)
 666     {
 667       /* Don't generate an error, just say which thread is current. */
 668       if (target_has_stack)
 669         printf_filtered (_("[Current thread is %d (%s)]\n"),
 670                          pid_to_thread_id (inferior_ptid),
 671                          target_tid_to_str (inferior_ptid));
 672       else
 673         error (_("No stack."));
 674       return;
 675     }
 676
 677   gdb_thread_select (uiout, tidstr, NULL);
 678 }
 679
 680 static int
 681 do_captured_thread_select (struct ui_out *uiout, void *tidstr)
 682 {
 683   int num;
 684   struct thread_info *tp;
 685
 686   num = value_as_long (parse_and_eval (tidstr));
 687
 688   tp = find_thread_id (num);
 689
 690   if (!tp)
 691     error (_("Thread ID %d not known."), num);
 692
 693   if (!thread_alive (tp))
 694     error (_("Thread ID %d has terminated."), num);
 695
 696   switch_to_thread (tp->ptid);
 697
 698   ui_out_text (uiout, "[Switching to thread ");
 699   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
 700   ui_out_text (uiout, " (");
 701   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
 702   ui_out_text (uiout, ")]");
 703
 704   print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 705   return GDB_RC_OK;
 706 }
 707
 708 enum gdb_rc
 709 gdb_thread_select (struct ui_out *uiout, char *tidstr, char **error_message)
 710 {
 711   return catch_exceptions_with_msg (uiout, do_captured_thread_select, tidstr,
 712                                     error_message, RETURN_MASK_ALL);
 713 }
 714
 715 /* Commands with a prefix of `thread'.  */
 716 struct cmd_list_element *thread_cmd_list = NULL;
 717
 718 void
 719 _initialize_thread (void)
 720 {
 721   static struct cmd_list_element *thread_apply_list = NULL;
 722
 723   add_info ("threads", info_threads_command,
 724             _("IDs of currently known threads."));
 725
 726   add_prefix_cmd ("thread", class_run, thread_command, _("\
 727 Use this command to switch between threads.\n\
 728 The new thread ID must be currently known."),
 729                   &thread_cmd_list, "thread ", 1, &cmdlist);
 730
 731   add_prefix_cmd ("apply", class_run, thread_apply_command,
 732                   _("Apply a command to a list of threads."),
 733                   &thread_apply_list, "thread apply ", 1, &thread_cmd_list);
 734
 735   add_cmd ("all", class_run, thread_apply_all_command,
 736            _("Apply a command to all threads."), &thread_apply_list);
 737
 738   if (!xdb_commands)
 739     add_com_alias ("t", "thread", class_run, 1);
 740 }