linuxthreads/internals.h

   1 /* Linuxthreads - a simple clone()-based implementation of Posix        */
   2 /* threads for Linux.                                                   */
   3 /* Copyright (C) 1996 Xavier Leroy (Xavier.Leroy@inria.fr)              */
   4 /*                                                                      */
   5 /* This program is free software; you can redistribute it and/or        */
   6 /* modify it under the terms of the GNU Library General Public License  */
   7 /* as published by the Free Software Foundation; either version 2       */
   8 /* of the License, or (at your option) any later version.               */
   9 /*                                                                      */
  10 /* This program is distributed in the hope that it will be useful,      */
  11 /* but WITHOUT ANY WARRANTY; without even the implied warranty of       */
  12 /* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        */
  13 /* GNU Library General Public License for more details.                 */
  14
  15 #ifndef _INTERNALS_H
  16 #define _INTERNALS_H    1
  17
  18 /* Internal data structures */
  19
  20 /* Includes */
  21
  22 #include <limits.h>
  23 #include <resolv.h>
  24 #include <setjmp.h>
  25 #include <signal.h>
  26 #include <unistd.h>
  27 #include <sys/types.h>
  28 #include <bits/libc-tsd.h> /* for _LIBC_TSD_KEY_N */
  29
  30 extern long int testandset (int *spinlock);
  31 extern int __compare_and_swap (long int *p, long int oldval, long int newval);
  32
  33 #include "pt-machine.h"
  34 #include "semaphore.h"
  35 #include "../linuxthreads_db/thread_dbP.h"
  36
  37 #ifndef THREAD_GETMEM
  38 # define THREAD_GETMEM(descr, member) descr->member
  39 #endif
  40 #ifndef THREAD_GETMEM_NC
  41 # define THREAD_GETMEM_NC(descr, member) descr->member
  42 #endif
  43 #ifndef THREAD_SETMEM
  44 # define THREAD_SETMEM(descr, member, value) descr->member = (value)
  45 #endif
  46 #ifndef THREAD_SETMEM_NC
  47 # define THREAD_SETMEM_NC(descr, member, value) descr->member = (value)
  48 #endif
  49
  50 /* Arguments passed to thread creation routine */
  51
  52 struct pthread_start_args {
  53   void * (*start_routine)(void *); /* function to run */
  54   void * arg;                   /* its argument */
  55   sigset_t mask;                /* initial signal mask for thread */
  56   int schedpolicy;              /* initial scheduling policy (if any) */
  57   struct sched_param schedparam; /* initial scheduling parameters (if any) */
  58 };
  59
  60
  61 /* We keep thread specific data in a special data structure, a two-level
  62    array.  The top-level array contains pointers to dynamically allocated
  63    arrays of a certain number of data pointers.  So we can implement a
  64    sparse array.  Each dynamic second-level array has
  65         PTHREAD_KEY_2NDLEVEL_SIZE
  66    entries.  This value shouldn't be too large.  */
  67 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  68
  69 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  70    keys in each subarray.  */
  71 #define PTHREAD_KEY_1STLEVEL_SIZE \
  72   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  73    / PTHREAD_KEY_2NDLEVEL_SIZE)
  74
  75 typedef void (*destr_function)(void *);
  76
  77 struct pthread_key_struct {
  78   int in_use;                   /* already allocated? */
  79   destr_function destr;         /* destruction routine */
  80 };
  81
  82
  83 #define PTHREAD_START_ARGS_INITIALIZER(fct) \
  84   { (void *(*) (void *)) fct, NULL, {{0, }}, 0, { 0 } }
  85
  86 /* The type of thread descriptors */
  87
  88 typedef struct _pthread_descr_struct * pthread_descr;
  89
  90 /* Callback interface for removing the thread from waiting on an
  91    object if it is cancelled while waiting or about to wait.
  92    This hold a pointer to the object, and a pointer to a function
  93    which ``extricates'' the thread from its enqueued state.
  94    The function takes two arguments: pointer to the wait object,
  95    and a pointer to the thread. It returns 1 if an extrication
  96    actually occured, and hence the thread must also be signalled.
  97    It returns 0 if the thread had already been extricated. */
  98
  99 typedef struct _pthread_extricate_struct {
 100     void *pu_object;
 101     int (*pu_extricate_func)(void *, pthread_descr);
 102 } pthread_extricate_if;
 103
 104 /* Atomic counter made possible by compare_and_swap */
 105
 106 struct pthread_atomic {
 107   long p_count;
 108   int p_spinlock;
 109 };
 110
 111 /* Context info for read write locks. The pthread_rwlock_info structure
 112    is information about a lock that has been read-locked by the thread
 113    in whose list this structure appears. The pthread_rwlock_context
 114    is embedded in the thread context and contains a pointer to the
 115    head of the list of lock info structures, as well as a count of
 116    read locks that are untracked, because no info structure could be
 117    allocated for them. */
 118
 119 struct _pthread_rwlock_t;
 120
 121 typedef struct _pthread_rwlock_info {
 122   struct _pthread_rwlock_info *pr_next;
 123   struct _pthread_rwlock_t *pr_lock;
 124   int pr_lock_count;
 125 } pthread_readlock_info;
 126
 127 struct _pthread_descr_struct {
 128   union {
 129     struct {
 130       pthread_descr self;       /* Pointer to this structure */
 131     } data;
 132     void *__padding[16];
 133   } p_header;
 134   pthread_descr p_nextlive, p_prevlive;
 135                                 /* Double chaining of active threads */
 136   pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
 137   pthread_descr p_nextlock;     /* can be on a queue and waiting on a lock */
 138   pthread_t p_tid;              /* Thread identifier */
 139   int p_pid;                    /* PID of Unix process */
 140   int p_priority;               /* Thread priority (== 0 if not realtime) */
 141   struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
 142   int p_signal;                 /* last signal received */
 143   sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
 144   sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
 145   char p_terminated;            /* true if terminated e.g. by pthread_exit */
 146   char p_detached;              /* true if detached */
 147   char p_exited;                /* true if the assoc. process terminated */
 148   void * p_retval;              /* placeholder for return value */
 149   int p_retcode;                /* placeholder for return code */
 150   pthread_descr p_joining;      /* thread joining on that thread or NULL */
 151   struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
 152   char p_cancelstate;           /* cancellation state */
 153   char p_canceltype;            /* cancellation type (deferred/async) */
 154   char p_canceled;              /* cancellation request pending */
 155   int * p_errnop;               /* pointer to used errno variable */
 156   int p_errno;                  /* error returned by last system call */
 157   int * p_h_errnop;             /* pointer to used h_errno variable */
 158   int p_h_errno;                /* error returned by last netdb function */
 159   char * p_in_sighandler;       /* stack address of sighandler, or NULL */
 160   char p_sigwaiting;            /* true if a sigwait() is in progress */
 161   struct pthread_start_args p_start_args; /* arguments for thread creation */
 162   void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
 163   void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
 164   int p_userstack;              /* nonzero if the user provided the stack */
 165   void *p_guardaddr;            /* address of guard area or NULL */
 166   size_t p_guardsize;           /* size of guard area */
 167   int p_nr;                     /* Index of descriptor in __pthread_handles */
 168   int p_report_events;          /* Nonzero if events must be reported.  */
 169   td_eventbuf_t p_eventbuf;     /* Data for event.  */
 170   struct pthread_atomic p_resume_count; /* number of times restart() was
 171                                            called on thread */
 172   char p_woken_by_cancel;       /* cancellation performed wakeup */
 173   char p_condvar_avail;         /* flag if conditional variable became avail */
 174   char p_sem_avail;             /* flag if semaphore became available */
 175   pthread_extricate_if *p_extricate; /* See above */
 176   pthread_readlock_info *p_readlock_list;  /* List of readlock info structs */
 177   pthread_readlock_info *p_readlock_free;  /* Free list of structs */
 178   int p_untracked_readlock_count;       /* Readlocks not tracked by list */
 179   struct __res_state *p_resp;   /* Pointer to resolver state */
 180   struct __res_state p_res;     /* per-thread resolver state */
 181   /* New elements must be added at the end.  */
 182 } __attribute__ ((aligned(32))); /* We need to align the structure so that
 183                                     doubles are aligned properly.  This is 8
 184                                     bytes on MIPS and 16 bytes on MIPS64.
 185                                     32 bytes might give better cache
 186                                     utilization.  */
 187
 188
 189 /* The type of thread handles. */
 190
 191 typedef struct pthread_handle_struct * pthread_handle;
 192
 193 struct pthread_handle_struct {
 194   struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */
 195   pthread_descr h_descr;        /* Thread descriptor or NULL if invalid */
 196   char * h_bottom;              /* Lowest address in the stack thread */
 197 };
 198
 199 /* The type of messages sent to the thread manager thread */
 200
 201 struct pthread_request {
 202   pthread_descr req_thread;     /* Thread doing the request */
 203   enum {                        /* Request kind */
 204     REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT,
 205     REQ_POST, REQ_DEBUG, REQ_KICK
 206   } req_kind;
 207   union {                       /* Arguments for request */
 208     struct {                    /* For REQ_CREATE: */
 209       const pthread_attr_t * attr; /* thread attributes */
 210       void * (*fn)(void *);     /*   start function */
 211       void * arg;               /*   argument to start function */
 212       sigset_t mask;            /*   signal mask */
 213     } create;
 214     struct {                    /* For REQ_FREE: */
 215       pthread_t thread_id;      /*   identifier of thread to free */
 216     } free;
 217     struct {                    /* For REQ_PROCESS_EXIT: */
 218       int code;                 /*   exit status */
 219     } exit;
 220     void * post;                /* For REQ_POST: the semaphore */
 221   } req_args;
 222 };
 223
 224
 225 /* Signals used for suspend/restart and for cancellation notification.  */
 226
 227 extern int __pthread_sig_restart;
 228 extern int __pthread_sig_cancel;
 229
 230 /* Signal used for interfacing with gdb */
 231
 232 extern int __pthread_sig_debug;
 233
 234 /* Global array of thread handles, used for validating a thread id
 235    and retrieving the corresponding thread descriptor. Also used for
 236    mapping the available stack segments. */
 237
 238 extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX];
 239
 240 /* Descriptor of the initial thread */
 241
 242 extern struct _pthread_descr_struct __pthread_initial_thread;
 243
 244 /* Descriptor of the manager thread */
 245
 246 extern struct _pthread_descr_struct __pthread_manager_thread;
 247
 248 /* Descriptor of the main thread */
 249
 250 extern pthread_descr __pthread_main_thread;
 251
 252 /* Limit between the stack of the initial thread (above) and the
 253    stacks of other threads (below). Aligned on a STACK_SIZE boundary.
 254    Initially 0, meaning that the current thread is (by definition)
 255    the initial thread. */
 256
 257 extern char *__pthread_initial_thread_bos;
 258
 259 /* Indicate whether at least one thread has a user-defined stack (if 1),
 260    or all threads have stacks supplied by LinuxThreads (if 0). */
 261
 262 extern int __pthread_nonstandard_stacks;
 263
 264 /* File descriptor for sending requests to the thread manager.
 265    Initially -1, meaning that __pthread_initialize_manager must be called. */
 266
 267 extern int __pthread_manager_request;
 268
 269 /* Other end of the pipe for sending requests to the thread manager. */
 270
 271 extern int __pthread_manager_reader;
 272
 273 /* Limits of the thread manager stack. */
 274
 275 extern char *__pthread_manager_thread_bos;
 276 extern char *__pthread_manager_thread_tos;
 277
 278 #ifdef FLOATING_STACKS
 279 /* Maximum stack size.  */
 280 extern size_t __pthread_max_stacksize;
 281 #endif
 282
 283 /* Pending request for a process-wide exit */
 284
 285 extern int __pthread_exit_requested, __pthread_exit_code;
 286
 287 /* Set to 1 by gdb if we're debugging */
 288
 289 extern volatile int __pthread_threads_debug;
 290
 291 /* Globally enabled events.  */
 292 extern volatile td_thr_events_t __pthread_threads_events;
 293
 294 /* Pointer to descriptor of thread with last event.  */
 295 extern volatile pthread_descr __pthread_last_event;
 296
 297 /* Flag which tells whether we are executing on SMP kernel. */
 298 extern int __pthread_smp_kernel;
 299
 300 /* Return the handle corresponding to a thread id */
 301
 302 static inline pthread_handle thread_handle(pthread_t id)
 303 {
 304   return &__pthread_handles[id % PTHREAD_THREADS_MAX];
 305 }
 306
 307 /* Validate a thread handle. Must have acquired h->h_spinlock before. */
 308
 309 static inline int invalid_handle(pthread_handle h, pthread_t id)
 310 {
 311   return h->h_descr == NULL || h->h_descr->p_tid != id || h->h_descr->p_terminated;
 312 }
 313
 314 static inline int nonexisting_handle(pthread_handle h, pthread_t id)
 315 {
 316   return h->h_descr == NULL || h->h_descr->p_tid != id;
 317 }
 318
 319 /* Fill in defaults left unspecified by pt-machine.h.  */
 320
 321 /* We round up a value with page size. */
 322 #ifndef page_roundup
 323 #define page_roundup(v,p) ((((size_t) (v)) + (p) - 1) & ~((p) - 1))
 324 #endif
 325
 326 /* The page size we can get from the system.  This should likely not be
 327    changed by the machine file but, you never know.  */
 328 #ifndef PAGE_SIZE
 329 #define PAGE_SIZE  (sysconf (_SC_PAGE_SIZE))
 330 #endif
 331
 332 /* The max size of the thread stack segments.  If the default
 333    THREAD_SELF implementation is used, this must be a power of two and
 334    a multiple of PAGE_SIZE.  */
 335 #ifndef STACK_SIZE
 336 #define STACK_SIZE  (2 * 1024 * 1024)
 337 #endif
 338
 339 /* The initial size of the thread stack.  Must be a multiple of PAGE_SIZE.  */
 340 #ifndef INITIAL_STACK_SIZE
 341 #define INITIAL_STACK_SIZE  (4 * PAGE_SIZE)
 342 #endif
 343
 344 /* Size of the thread manager stack. The "- 32" avoids wasting space
 345    with some malloc() implementations. */
 346 #ifndef THREAD_MANAGER_STACK_SIZE
 347 #define THREAD_MANAGER_STACK_SIZE  (2 * PAGE_SIZE - 32)
 348 #endif
 349
 350 /* The base of the "array" of thread stacks.  The array will grow down from
 351    here.  Defaults to the calculated bottom of the initial application
 352    stack.  */
 353 #ifndef THREAD_STACK_START_ADDRESS
 354 #define THREAD_STACK_START_ADDRESS  __pthread_initial_thread_bos
 355 #endif
 356
 357 /* Get some notion of the current stack.  Need not be exactly the top
 358    of the stack, just something somewhere in the current frame.  */
 359 #ifndef CURRENT_STACK_FRAME
 360 #define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 361 #endif
 362
 363 /* Recover thread descriptor for the current thread */
 364
 365 extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
 366
 367 static inline pthread_descr thread_self (void) __attribute__ ((const));
 368 static inline pthread_descr thread_self (void)
 369 {
 370 #ifdef THREAD_SELF
 371   return THREAD_SELF;
 372 #else
 373   char *sp = CURRENT_STACK_FRAME;
 374   if (sp >= __pthread_initial_thread_bos)
 375     return &__pthread_initial_thread;
 376   else if (sp >= __pthread_manager_thread_bos
 377            && sp < __pthread_manager_thread_tos)
 378     return &__pthread_manager_thread;
 379   else if (__pthread_nonstandard_stacks)
 380     return __pthread_find_self();
 381   else
 382     return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
 383 #endif
 384 }
 385
 386 /* If MEMORY_BARRIER isn't defined in pt-machine.h, assume the architecture
 387    doesn't need a memory barrier instruction (e.g. Intel x86).  Some
 388    architectures distinguish between full, read and write barriers.  */
 389
 390 #ifndef MEMORY_BARRIER
 391 #define MEMORY_BARRIER()
 392 #endif
 393 #ifndef READ_MEMORY_BARRIER
 394 #define READ_MEMORY_BARRIER() MEMORY_BARRIER()
 395 #endif
 396 #ifndef WRITE_MEMORY_BARRIER
 397 #define WRITE_MEMORY_BARRIER() MEMORY_BARRIER()
 398 #endif
 399
 400 /* Max number of times we must spin on a spinlock calling sched_yield().
 401    After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
 402
 403 #ifndef MAX_SPIN_COUNT
 404 #define MAX_SPIN_COUNT 50
 405 #endif
 406
 407 /* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
 408    after MAX_SPIN_COUNT iterations of sched_yield().
 409    With the 2.0 and 2.1 kernels, this MUST BE > 2ms.
 410    (Otherwise the kernel does busy-waiting for realtime threads,
 411     giving other threads no chance to run.) */
 412
 413 #ifndef SPIN_SLEEP_DURATION
 414 #define SPIN_SLEEP_DURATION 2000001
 415 #endif
 416
 417 /* Debugging */
 418
 419 #ifdef DEBUG
 420 #include <assert.h>
 421 #define ASSERT assert
 422 #define MSG __pthread_message
 423 #else
 424 #define ASSERT(x)
 425 #define MSG(msg,arg...)
 426 #endif
 427
 428 /* Internal global functions */
 429
 430 extern void __pthread_destroy_specifics (void);
 431 extern void __pthread_perform_cleanup (void);
 432 extern int __pthread_initialize_manager (void);
 433 extern void __pthread_message (char * fmt, ...);
 434 extern int __pthread_manager (void *reqfd);
 435 extern int __pthread_manager_event (void *reqfd);
 436 extern void __pthread_manager_sighandler (int sig);
 437 extern void __pthread_reset_main_thread (void);
 438 extern void __pthread_once_fork_prepare (void);
 439 extern void __pthread_once_fork_parent (void);
 440 extern void __pthread_once_fork_child (void);
 441 extern void __flockfilelist (void);
 442 extern void __funlockfilelist (void);
 443 extern void __fresetlockfiles (void);
 444 extern void __pthread_manager_adjust_prio (int thread_prio);
 445 extern void __pthread_initialize_minimal (void);
 446
 447 extern int __pthread_attr_setguardsize (pthread_attr_t *__attr,
 448                                         size_t __guardsize);
 449 extern int __pthread_attr_getguardsize (const pthread_attr_t *__attr,
 450                                         size_t *__guardsize);
 451 extern int __pthread_attr_setstackaddr (pthread_attr_t *__attr,
 452                                         void *__stackaddr);
 453 extern int __pthread_attr_getstackaddr (const pthread_attr_t *__attr,
 454                                         void **__stackaddr);
 455 extern int __pthread_attr_setstacksize (pthread_attr_t *__attr,
 456                                         size_t __stacksize);
 457 extern int __pthread_attr_getstacksize (const pthread_attr_t *__attr,
 458                                         size_t *__stacksize);
 459 extern int __pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
 460                                     size_t __stacksize);
 461 extern int __pthread_attr_getstack (const pthread_attr_t *__attr, void **__stackaddr,
 462                                     size_t *__stacksize);
 463 extern int __pthread_getconcurrency (void);
 464 extern int __pthread_setconcurrency (int __level);
 465 extern int __pthread_mutex_timedlock (pthread_mutex_t *__mutex,
 466                                       const struct timespec *__abstime);
 467 extern int __pthread_mutexattr_getpshared (const pthread_mutexattr_t *__attr,
 468                                            int *__pshared);
 469 extern int __pthread_mutexattr_setpshared (pthread_mutexattr_t *__attr,
 470                                            int __pshared);
 471 extern int __pthread_mutexattr_gettype (const pthread_mutexattr_t *__attr,
 472                                         int *__kind);
 473 extern void __pthread_kill_other_threads_np (void);
 474
 475 extern void __pthread_restart_old(pthread_descr th);
 476 extern void __pthread_suspend_old(pthread_descr self);
 477 extern int __pthread_timedsuspend_old(pthread_descr self, const struct timespec *abs);
 478
 479 extern void __pthread_restart_new(pthread_descr th);
 480 extern void __pthread_suspend_new(pthread_descr self);
 481 extern int __pthread_timedsuspend_new(pthread_descr self, const struct timespec *abs);
 482
 483 extern void __pthread_wait_for_restart_signal(pthread_descr self);
 484
 485 extern int __pthread_yield (void);
 486
 487 extern int __pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
 488                                          __const struct timespec *__restrict
 489                                          __abstime);
 490 extern int __pthread_rwlock_timedwrlock (pthread_rwlock_t *__restrict __rwlock,
 491                                          __const struct timespec *__restrict
 492                                          __abstime);
 493 extern int __pthread_rwlockattr_destroy (pthread_rwlockattr_t *__attr);
 494
 495 extern int __pthread_barrierattr_getpshared (__const pthread_barrierattr_t *
 496                                              __restrict __attr,
 497                                              int *__restrict __pshared);
 498
 499 extern int __pthread_spin_lock (pthread_spinlock_t *__lock);
 500 extern int __pthread_spin_trylock (pthread_spinlock_t *__lock);
 501 extern int __pthread_spin_unlock (pthread_spinlock_t *__lock);
 502 extern int __pthread_spin_init (pthread_spinlock_t *__lock, int __pshared);
 503 extern int __pthread_spin_destroy (pthread_spinlock_t *__lock);
 504
 505
 506 /* Global pointers to old or new suspend functions */
 507
 508 extern void (*__pthread_restart)(pthread_descr);
 509 extern void (*__pthread_suspend)(pthread_descr);
 510 extern int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *);
 511
 512 /* Prototypes for the function without cancelation support when the
 513    normal version has it.  */
 514 extern int __libc_close (int fd);
 515 extern int __libc_nanosleep (const struct timespec *requested_time,
 516                              struct timespec *remaining);
 517 /* Prototypes for some of the new semaphore functions.  */
 518 extern int __new_sem_post (sem_t * sem);
 519 extern int __new_sem_init (sem_t *__sem, int __pshared, unsigned int __value);
 520 extern int __new_sem_wait (sem_t *__sem);
 521 extern int __new_sem_trywait (sem_t *__sem);
 522 extern int __new_sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval);
 523 extern int __new_sem_destroy (sem_t *__sem);
 524
 525 /* Prototypes for compatibility functions.  */
 526 extern int __pthread_attr_init_2_1 (pthread_attr_t *__attr);
 527 extern int __pthread_attr_init_2_0 (pthread_attr_t *__attr);
 528 extern int __pthread_create_2_1 (pthread_t *__restrict __thread,
 529                                  const pthread_attr_t *__attr,
 530                                  void *(*__start_routine) (void *),
 531                                  void *__restrict __arg);
 532 extern int __pthread_create_2_0 (pthread_t *__restrict thread,
 533                                  const pthread_attr_t *__attr,
 534                                  void *(*__start_routine) (void *),
 535                                  void *__restrict arg);
 536
 537 /* The functions called the signal events.  */
 538 extern void __linuxthreads_create_event (void);
 539 extern void __linuxthreads_death_event (void);
 540 extern void __linuxthreads_reap_event (void);
 541
 542 /* This function is called to initialize the pthread library.  */
 543 extern void __pthread_initialize (void);
 544
 545 #endif /* internals.h */