gdb/thread.c

   1 /* Multi-process/thread control for GDB, the GNU debugger.
   2
   3    Copyright 1986, 1987, 1988, 1993, 1994, 1995, 1996, 1997, 1998,
   4    1999, 2000, 2001, 2002 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., 59 Temple Place - Suite 330,
  23    Boston, MA 02111-1307, 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 "command.h"
  34 #include "gdbcmd.h"
  35 #include "regcache.h"
  36 #include "gdb.h"
  37 #include "gdb_string.h"
  38
  39 #include <ctype.h>
  40 #include <sys/types.h>
  41 #include <signal.h>
  42 #include "ui-out.h"
  43
  44 /*#include "lynxos-core.h" */
  45
  46 /* Definition of struct thread_info exported to gdbthread.h */
  47
  48 /* Prototypes for exported functions. */
  49
  50 void _initialize_thread (void);
  51
  52 /* Prototypes for local functions. */
  53
  54 static struct thread_info *thread_list = NULL;
  55 static int highest_thread_num;
  56
  57 static struct thread_info *find_thread_id (int num);
  58
  59 static void thread_command (char *tidstr, int from_tty);
  60 static void thread_apply_all_command (char *, int);
  61 static int thread_alive (struct thread_info *);
  62 static void info_threads_command (char *, int);
  63 static void thread_apply_command (char *, int);
  64 static void restore_current_thread (ptid_t);
  65 static void switch_to_thread (ptid_t ptid);
  66 static void prune_threads (void);
  67
  68 void
  69 delete_step_resume_breakpoint (void *arg)
  70 {
  71   struct breakpoint **breakpointp = (struct breakpoint **) arg;
  72   struct thread_info *tp;
  73
  74   if (*breakpointp != NULL)
  75     {
  76       delete_breakpoint (*breakpointp);
  77       for (tp = thread_list; tp; tp = tp->next)
  78         if (tp->step_resume_breakpoint == *breakpointp)
  79           tp->step_resume_breakpoint = NULL;
  80
  81       *breakpointp = NULL;
  82     }
  83 }
  84
  85 static void
  86 free_thread (struct thread_info *tp)
  87 {
  88   /* NOTE: this will take care of any left-over step_resume breakpoints,
  89      but not any user-specified thread-specific breakpoints. */
  90   if (tp->step_resume_breakpoint)
  91     delete_breakpoint (tp->step_resume_breakpoint);
  92
  93   /* FIXME: do I ever need to call the back-end to give it a
  94      chance at this private data before deleting the thread?  */
  95   if (tp->private)
  96     xfree (tp->private);
  97
  98   xfree (tp);
  99 }
 100
 101 void
 102 init_thread_list (void)
 103 {
 104   struct thread_info *tp, *tpnext;
 105
 106   highest_thread_num = 0;
 107   if (!thread_list)
 108     return;
 109
 110   for (tp = thread_list; tp; tp = tpnext)
 111     {
 112       tpnext = tp->next;
 113       free_thread (tp);
 114     }
 115
 116   thread_list = NULL;
 117 }
 118
 119 /* add_thread now returns a pointer to the new thread_info,
 120    so that back_ends can initialize their private data.  */
 121
 122 struct thread_info *
 123 add_thread (ptid_t ptid)
 124 {
 125   struct thread_info *tp;
 126
 127   tp = (struct thread_info *) xmalloc (sizeof (*tp));
 128   memset (tp, 0, sizeof (*tp));
 129   tp->ptid = ptid;
 130   tp->num = ++highest_thread_num;
 131   tp->next = thread_list;
 132   thread_list = tp;
 133   return tp;
 134 }
 135
 136 void
 137 delete_thread (ptid_t ptid)
 138 {
 139   struct thread_info *tp, *tpprev;
 140
 141   tpprev = NULL;
 142
 143   for (tp = thread_list; tp; tpprev = tp, tp = tp->next)
 144     if (ptid_equal (tp->ptid, ptid))
 145       break;
 146
 147   if (!tp)
 148     return;
 149
 150   if (tpprev)
 151     tpprev->next = tp->next;
 152   else
 153     thread_list = tp->next;
 154
 155   free_thread (tp);
 156 }
 157
 158 static struct thread_info *
 159 find_thread_id (int num)
 160 {
 161   struct thread_info *tp;
 162
 163   for (tp = thread_list; tp; tp = tp->next)
 164     if (tp->num == num)
 165       return tp;
 166
 167   return NULL;
 168 }
 169
 170 /* Find a thread_info by matching PTID.  */
 171 struct thread_info *
 172 find_thread_pid (ptid_t ptid)
 173 {
 174   struct thread_info *tp;
 175
 176   for (tp = thread_list; tp; tp = tp->next)
 177     if (ptid_equal (tp->ptid, ptid))
 178       return tp;
 179
 180   return NULL;
 181 }
 182
 183 /*
 184  * Thread iterator function.
 185  *
 186  * Calls a callback function once for each thread, so long as
 187  * the callback function returns false.  If the callback function
 188  * returns true, the iteration will end and the current thread
 189  * will be returned.  This can be useful for implementing a
 190  * search for a thread with arbitrary attributes, or for applying
 191  * some operation to every thread.
 192  *
 193  * FIXME: some of the existing functionality, such as
 194  * "Thread apply all", might be rewritten using this functionality.
 195  */
 196
 197 struct thread_info *
 198 iterate_over_threads (int (*callback) (struct thread_info *, void *),
 199                       void *data)
 200 {
 201   struct thread_info *tp;
 202
 203   for (tp = thread_list; tp; tp = tp->next)
 204     if ((*callback) (tp, data))
 205       return tp;
 206
 207   return NULL;
 208 }
 209
 210 int
 211 valid_thread_id (int num)
 212 {
 213   struct thread_info *tp;
 214
 215   for (tp = thread_list; tp; tp = tp->next)
 216     if (tp->num == num)
 217       return 1;
 218
 219   return 0;
 220 }
 221
 222 int
 223 pid_to_thread_id (ptid_t ptid)
 224 {
 225   struct thread_info *tp;
 226
 227   for (tp = thread_list; tp; tp = tp->next)
 228     if (ptid_equal (tp->ptid, ptid))
 229       return tp->num;
 230
 231   return 0;
 232 }
 233
 234 ptid_t
 235 thread_id_to_pid (int num)
 236 {
 237   struct thread_info *thread = find_thread_id (num);
 238   if (thread)
 239     return thread->ptid;
 240   else
 241     return pid_to_ptid (-1);
 242 }
 243
 244 int
 245 in_thread_list (ptid_t ptid)
 246 {
 247   struct thread_info *tp;
 248
 249   for (tp = thread_list; tp; tp = tp->next)
 250     if (ptid_equal (tp->ptid, ptid))
 251       return 1;
 252
 253   return 0;                     /* Never heard of 'im */
 254 }
 255
 256 /* Print a list of thread ids currently known, and the total number of
 257    threads. To be used from within catch_errors. */
 258 static int
 259 do_captured_list_thread_ids (struct ui_out *uiout,
 260                              void *arg)
 261 {
 262   struct thread_info *tp;
 263   int num = 0;
 264
 265   ui_out_tuple_begin (uiout, "thread-ids");
 266
 267   for (tp = thread_list; tp; tp = tp->next)
 268     {
 269       num++;
 270       ui_out_field_int (uiout, "thread-id", tp->num);
 271     }
 272
 273   ui_out_tuple_end (uiout);
 274   ui_out_field_int (uiout, "number-of-threads", num);
 275   return GDB_RC_OK;
 276 }
 277
 278 /* Official gdblib interface function to get a list of thread ids and
 279    the total number. */
 280 enum gdb_rc
 281 gdb_list_thread_ids (struct ui_out *uiout)
 282 {
 283   return catch_exceptions (uiout, do_captured_list_thread_ids, NULL,
 284                            NULL, RETURN_MASK_ALL);
 285 }
 286
 287 /* Load infrun state for the thread PID.  */
 288
 289 void
 290 load_infrun_state (ptid_t ptid,
 291                    CORE_ADDR *prev_pc,
 292                    CORE_ADDR *prev_func_start,
 293                    char **prev_func_name,
 294                    int *trap_expected,
 295                    struct breakpoint **step_resume_breakpoint,
 296                    struct breakpoint **through_sigtramp_breakpoint,
 297                    CORE_ADDR *step_range_start,
 298                    CORE_ADDR *step_range_end,
 299                    CORE_ADDR *step_frame_address,
 300                    int *handling_longjmp,
 301                    int *another_trap,
 302                    int *stepping_through_solib_after_catch,
 303                    bpstat *stepping_through_solib_catchpoints,
 304                    int *stepping_through_sigtramp,
 305                    int *current_line,
 306                    struct symtab **current_symtab,
 307                    CORE_ADDR *step_sp)
 308 {
 309   struct thread_info *tp;
 310
 311   /* If we can't find the thread, then we're debugging a single threaded
 312      process.  No need to do anything in that case.  */
 313   tp = find_thread_id (pid_to_thread_id (ptid));
 314   if (tp == NULL)
 315     return;
 316
 317   *prev_pc = tp->prev_pc;
 318   *prev_func_start = tp->prev_func_start;
 319   *prev_func_name = tp->prev_func_name;
 320   *trap_expected = tp->trap_expected;
 321   *step_resume_breakpoint = tp->step_resume_breakpoint;
 322   *through_sigtramp_breakpoint = tp->through_sigtramp_breakpoint;
 323   *step_range_start = tp->step_range_start;
 324   *step_range_end = tp->step_range_end;
 325   *step_frame_address = tp->step_frame_address;
 326   *handling_longjmp = tp->handling_longjmp;
 327   *another_trap = tp->another_trap;
 328   *stepping_through_solib_after_catch = tp->stepping_through_solib_after_catch;
 329   *stepping_through_solib_catchpoints = tp->stepping_through_solib_catchpoints;
 330   *stepping_through_sigtramp = tp->stepping_through_sigtramp;
 331   *current_line = tp->current_line;
 332   *current_symtab = tp->current_symtab;
 333   *step_sp = tp->step_sp;
 334 }
 335
 336 /* Save infrun state for the thread PID.  */
 337
 338 void
 339 save_infrun_state (ptid_t ptid,
 340                    CORE_ADDR prev_pc,
 341                    CORE_ADDR prev_func_start,
 342                    char *prev_func_name,
 343                    int trap_expected,
 344                    struct breakpoint *step_resume_breakpoint,
 345                    struct breakpoint *through_sigtramp_breakpoint,
 346                    CORE_ADDR step_range_start,
 347                    CORE_ADDR step_range_end,
 348                    CORE_ADDR step_frame_address,
 349                    int handling_longjmp,
 350                    int another_trap,
 351                    int stepping_through_solib_after_catch,
 352                    bpstat stepping_through_solib_catchpoints,
 353                    int stepping_through_sigtramp,
 354                    int current_line,
 355                    struct symtab *current_symtab,
 356                    CORE_ADDR step_sp)
 357 {
 358   struct thread_info *tp;
 359
 360   /* If we can't find the thread, then we're debugging a single-threaded
 361      process.  Nothing to do in that case.  */
 362   tp = find_thread_id (pid_to_thread_id (ptid));
 363   if (tp == NULL)
 364     return;
 365
 366   tp->prev_pc = prev_pc;
 367   tp->prev_func_start = prev_func_start;
 368   tp->prev_func_name = prev_func_name;
 369   tp->trap_expected = trap_expected;
 370   tp->step_resume_breakpoint = step_resume_breakpoint;
 371   tp->through_sigtramp_breakpoint = through_sigtramp_breakpoint;
 372   tp->step_range_start = step_range_start;
 373   tp->step_range_end = step_range_end;
 374   tp->step_frame_address = step_frame_address;
 375   tp->handling_longjmp = handling_longjmp;
 376   tp->another_trap = another_trap;
 377   tp->stepping_through_solib_after_catch = stepping_through_solib_after_catch;
 378   tp->stepping_through_solib_catchpoints = stepping_through_solib_catchpoints;
 379   tp->stepping_through_sigtramp = stepping_through_sigtramp;
 380   tp->current_line = current_line;
 381   tp->current_symtab = current_symtab;
 382   tp->step_sp = step_sp;
 383 }
 384
 385 /* Return true if TP is an active thread. */
 386 static int
 387 thread_alive (struct thread_info *tp)
 388 {
 389   if (PIDGET (tp->ptid) == -1)
 390     return 0;
 391   if (!target_thread_alive (tp->ptid))
 392     {
 393       tp->ptid = pid_to_ptid (-1);      /* Mark it as dead */
 394       return 0;
 395     }
 396   return 1;
 397 }
 398
 399 static void
 400 prune_threads (void)
 401 {
 402   struct thread_info *tp, *next;
 403
 404   for (tp = thread_list; tp; tp = next)
 405     {
 406       next = tp->next;
 407       if (!thread_alive (tp))
 408         delete_thread (tp->ptid);
 409     }
 410 }
 411
 412 /* Print information about currently known threads
 413
 414  * Note: this has the drawback that it _really_ switches
 415  *       threads, which frees the frame cache.  A no-side
 416  *       effects info-threads command would be nicer.
 417  */
 418
 419 static void
 420 info_threads_command (char *arg, int from_tty)
 421 {
 422   struct thread_info *tp;
 423   ptid_t current_ptid;
 424   struct frame_info *cur_frame;
 425   int saved_frame_level = frame_relative_level (selected_frame);
 426   int counter;
 427   char *extra_info;
 428
 429   /* Avoid coredumps which would happen if we tried to access a NULL
 430      selected_frame.  */
 431   if (!target_has_stack)
 432     error ("No stack.");
 433
 434   prune_threads ();
 435   target_find_new_threads ();
 436   current_ptid = inferior_ptid;
 437   for (tp = thread_list; tp; tp = tp->next)
 438     {
 439       if (ptid_equal (tp->ptid, current_ptid))
 440         printf_filtered ("* ");
 441       else
 442         printf_filtered ("  ");
 443
 444 #ifdef HPUXHPPA
 445       printf_filtered ("%d %s", tp->num, target_tid_to_str (tp->ptid));
 446 #else
 447       printf_filtered ("%d %s", tp->num, target_pid_to_str (tp->ptid));
 448 #endif
 449
 450       extra_info = target_extra_thread_info (tp);
 451       if (extra_info)
 452         printf_filtered (" (%s)", extra_info);
 453       puts_filtered ("  ");
 454
 455       switch_to_thread (tp->ptid);
 456       if (selected_frame)
 457         print_only_stack_frame (selected_frame, -1, 0);
 458       else
 459         printf_filtered ("[No stack.]\n");
 460     }
 461
 462   switch_to_thread (current_ptid);
 463
 464   /* Code below copied from "up_silently_base" in "stack.c".
 465    * It restores the frame set by the user before the "info threads"
 466    * command.  We have finished the info-threads display by switching
 467    * back to the current thread.  That switch has put us at the top
 468    * of the stack (leaf frame).
 469    */
 470   counter = saved_frame_level;
 471   cur_frame = find_relative_frame (selected_frame, &counter);
 472   if (counter != 0)
 473     {
 474       /* Ooops, can't restore, tell user where we are. */
 475       warning ("Couldn't restore frame in current thread, at frame 0");
 476       print_stack_frame (selected_frame, -1, 0);
 477     }
 478   else
 479     {
 480       select_frame (cur_frame);
 481     }
 482
 483   /* re-show current frame. */
 484   show_stack_frame (cur_frame);
 485 }
 486
 487 /* Switch from one thread to another. */
 488
 489 static void
 490 switch_to_thread (ptid_t ptid)
 491 {
 492   if (ptid_equal (ptid, inferior_ptid))
 493     return;
 494
 495   inferior_ptid = ptid;
 496   flush_cached_frames ();
 497   registers_changed ();
 498   stop_pc = read_pc ();
 499   select_frame (get_current_frame ());
 500 }
 501
 502 static void
 503 restore_current_thread (ptid_t ptid)
 504 {
 505   if (! ptid_equal (ptid, inferior_ptid))
 506     {
 507       switch_to_thread (ptid);
 508       print_stack_frame (get_current_frame (), 0, -1);
 509     }
 510 }
 511
 512 struct current_thread_cleanup
 513 {
 514   ptid_t inferior_ptid;
 515 };
 516
 517 static void
 518 do_restore_current_thread_cleanup (void *arg)
 519 {
 520   struct current_thread_cleanup *old = arg;
 521   restore_current_thread (old->inferior_ptid);
 522   xfree (old);
 523 }
 524
 525 static struct cleanup *
 526 make_cleanup_restore_current_thread (ptid_t inferior_ptid)
 527 {
 528   struct current_thread_cleanup *old
 529     = xmalloc (sizeof (struct current_thread_cleanup));
 530   old->inferior_ptid = inferior_ptid;
 531   return make_cleanup (do_restore_current_thread_cleanup, old);
 532 }
 533
 534 /* Apply a GDB command to a list of threads.  List syntax is a whitespace
 535    seperated list of numbers, or ranges, or the keyword `all'.  Ranges consist
 536    of two numbers seperated by a hyphen.  Examples:
 537
 538    thread apply 1 2 7 4 backtrace       Apply backtrace cmd to threads 1,2,7,4
 539    thread apply 2-7 9 p foo(1)  Apply p foo(1) cmd to threads 2->7 & 9
 540    thread apply all p x/i $pc   Apply x/i $pc cmd to all threads
 541  */
 542
 543 static void
 544 thread_apply_all_command (char *cmd, int from_tty)
 545 {
 546   struct thread_info *tp;
 547   struct cleanup *old_chain;
 548   struct cleanup *saved_cmd_cleanup_chain;
 549   char *saved_cmd;
 550
 551   if (cmd == NULL || *cmd == '\000')
 552     error ("Please specify a command following the thread ID list");
 553
 554   old_chain = make_cleanup_restore_current_thread (inferior_ptid);
 555
 556   /* It is safe to update the thread list now, before
 557      traversing it for "thread apply all".  MVS */
 558   target_find_new_threads ();
 559
 560   /* Save a copy of the command in case it is clobbered by
 561      execute_command */
 562   saved_cmd = xstrdup (cmd);
 563   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 564   for (tp = thread_list; tp; tp = tp->next)
 565     if (thread_alive (tp))
 566       {
 567         switch_to_thread (tp->ptid);
 568 #ifdef HPUXHPPA
 569         printf_filtered ("\nThread %d (%s):\n",
 570                          tp->num,
 571                          target_tid_to_str (inferior_ptid));
 572 #else
 573         printf_filtered ("\nThread %d (%s):\n", tp->num,
 574                          target_pid_to_str (inferior_ptid));
 575 #endif
 576         execute_command (cmd, from_tty);
 577         strcpy (cmd, saved_cmd); /* Restore exact command used previously */
 578       }
 579
 580   do_cleanups (saved_cmd_cleanup_chain);
 581   do_cleanups (old_chain);
 582 }
 583
 584 static void
 585 thread_apply_command (char *tidlist, int from_tty)
 586 {
 587   char *cmd;
 588   char *p;
 589   struct cleanup *old_chain;
 590   struct cleanup *saved_cmd_cleanup_chain;
 591   char *saved_cmd;
 592
 593   if (tidlist == NULL || *tidlist == '\000')
 594     error ("Please specify a thread ID list");
 595
 596   for (cmd = tidlist; *cmd != '\000' && !isalpha (*cmd); cmd++);
 597
 598   if (*cmd == '\000')
 599     error ("Please specify a command following the thread ID list");
 600
 601   old_chain = make_cleanup_restore_current_thread (inferior_ptid);
 602
 603   /* Save a copy of the command in case it is clobbered by
 604      execute_command */
 605   saved_cmd = xstrdup (cmd);
 606   saved_cmd_cleanup_chain = make_cleanup (xfree, (void *) saved_cmd);
 607   while (tidlist < cmd)
 608     {
 609       struct thread_info *tp;
 610       int start, end;
 611
 612       start = strtol (tidlist, &p, 10);
 613       if (p == tidlist)
 614         error ("Error parsing %s", tidlist);
 615       tidlist = p;
 616
 617       while (*tidlist == ' ' || *tidlist == '\t')
 618         tidlist++;
 619
 620       if (*tidlist == '-')      /* Got a range of IDs? */
 621         {
 622           tidlist++;            /* Skip the - */
 623           end = strtol (tidlist, &p, 10);
 624           if (p == tidlist)
 625             error ("Error parsing %s", tidlist);
 626           tidlist = p;
 627
 628           while (*tidlist == ' ' || *tidlist == '\t')
 629             tidlist++;
 630         }
 631       else
 632         end = start;
 633
 634       for (; start <= end; start++)
 635         {
 636           tp = find_thread_id (start);
 637
 638           if (!tp)
 639             warning ("Unknown thread %d.", start);
 640           else if (!thread_alive (tp))
 641             warning ("Thread %d has terminated.", start);
 642           else
 643             {
 644               switch_to_thread (tp->ptid);
 645 #ifdef HPUXHPPA
 646               printf_filtered ("\nThread %d (%s):\n", tp->num,
 647                                target_tid_to_str (inferior_ptid));
 648 #else
 649               printf_filtered ("\nThread %d (%s):\n", tp->num,
 650                                target_pid_to_str (inferior_ptid));
 651 #endif
 652               execute_command (cmd, from_tty);
 653               strcpy (cmd, saved_cmd);  /* Restore exact command used previously */
 654             }
 655         }
 656     }
 657
 658   do_cleanups (saved_cmd_cleanup_chain);
 659   do_cleanups (old_chain);
 660 }
 661
 662 /* Switch to the specified thread.  Will dispatch off to thread_apply_command
 663    if prefix of arg is `apply'.  */
 664
 665 static void
 666 thread_command (char *tidstr, int from_tty)
 667 {
 668   if (!tidstr)
 669     {
 670       /* Don't generate an error, just say which thread is current. */
 671       if (target_has_stack)
 672         printf_filtered ("[Current thread is %d (%s)]\n",
 673                          pid_to_thread_id (inferior_ptid),
 674 #if defined(HPUXHPPA)
 675                          target_tid_to_str (inferior_ptid)
 676 #else
 677                          target_pid_to_str (inferior_ptid)
 678 #endif
 679           );
 680       else
 681         error ("No stack.");
 682       return;
 683     }
 684
 685   gdb_thread_select (uiout, tidstr);
 686 }
 687
 688 static int
 689 do_captured_thread_select (struct ui_out *uiout,
 690                            void *tidstr)
 691 {
 692   int num;
 693   struct thread_info *tp;
 694
 695   num = value_as_long (parse_and_eval (tidstr));
 696
 697   tp = find_thread_id (num);
 698
 699   if (!tp)
 700     error ("Thread ID %d not known.", num);
 701
 702   if (!thread_alive (tp))
 703     error ("Thread ID %d has terminated.\n", num);
 704
 705   switch_to_thread (tp->ptid);
 706
 707   ui_out_text (uiout, "[Switching to thread ");
 708   ui_out_field_int (uiout, "new-thread-id", pid_to_thread_id (inferior_ptid));
 709   ui_out_text (uiout, " (");
 710 #if defined(HPUXHPPA)
 711   ui_out_text (uiout, target_tid_to_str (inferior_ptid));
 712 #else
 713   ui_out_text (uiout, target_pid_to_str (inferior_ptid));
 714 #endif
 715   ui_out_text (uiout, ")]");
 716
 717   print_stack_frame (selected_frame, frame_relative_level (selected_frame), 1);
 718   return GDB_RC_OK;
 719 }
 720
 721 enum gdb_rc
 722 gdb_thread_select (struct ui_out *uiout,
 723                    char *tidstr)
 724 {
 725   return catch_exceptions (uiout, do_captured_thread_select, tidstr,
 726                            NULL, RETURN_MASK_ALL);
 727 }
 728
 729 /* Commands with a prefix of `thread'.  */
 730 struct cmd_list_element *thread_cmd_list = NULL;
 731
 732 void
 733 _initialize_thread (void)
 734 {
 735   static struct cmd_list_element *thread_apply_list = NULL;
 736
 737   add_info ("threads", info_threads_command,
 738             "IDs of currently known threads.");
 739
 740   add_prefix_cmd ("thread", class_run, thread_command,
 741                   "Use this command to switch between threads.\n\
 742 The new thread ID must be currently known.", &thread_cmd_list, "thread ", 1,
 743                   &cmdlist);
 744
 745   add_prefix_cmd ("apply", class_run, thread_apply_command,
 746                   "Apply a command to a list of threads.",
 747                   &thread_apply_list, "apply ", 1, &thread_cmd_list);
 748
 749   add_cmd ("all", class_run, thread_apply_all_command,
 750            "Apply a command to all threads.",
 751            &thread_apply_list);
 752
 753   if (!xdb_commands)
 754     add_com_alias ("t", "thread", class_run, 1);
 755 }