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 <stackinfo.h>
  28 #include <sys/types.h>
  29 #include <bits/libc-tsd.h> /* for _LIBC_TSD_KEY_N */
  30
  31 extern long int testandset (int *spinlock);
  32 extern int __compare_and_swap (long int *p, long int oldval, long int newval);
  33
  34 #include "pt-machine.h"
  35 #include "semaphore.h"
  36 #include "../linuxthreads_db/thread_dbP.h"
  37 #include <hp-timing.h>
  38
  39 #ifndef THREAD_GETMEM
  40 # define THREAD_GETMEM(descr, member) descr->member
  41 #endif
  42 #ifndef THREAD_GETMEM_NC
  43 # define THREAD_GETMEM_NC(descr, member) descr->member
  44 #endif
  45 #ifndef THREAD_SETMEM
  46 # define THREAD_SETMEM(descr, member, value) descr->member = (value)
  47 #endif
  48 #ifndef THREAD_SETMEM_NC
  49 # define THREAD_SETMEM_NC(descr, member, value) descr->member = (value)
  50 #endif
  51
  52 /* Arguments passed to thread creation routine */
  53
  54 struct pthread_start_args {
  55   void * (*start_routine)(void *); /* function to run */
  56   void * arg;                   /* its argument */
  57   sigset_t mask;                /* initial signal mask for thread */
  58   int schedpolicy;              /* initial scheduling policy (if any) */
  59   struct sched_param schedparam; /* initial scheduling parameters (if any) */
  60 };
  61
  62
  63 /* We keep thread specific data in a special data structure, a two-level
  64    array.  The top-level array contains pointers to dynamically allocated
  65    arrays of a certain number of data pointers.  So we can implement a
  66    sparse array.  Each dynamic second-level array has
  67         PTHREAD_KEY_2NDLEVEL_SIZE
  68    entries.  This value shouldn't be too large.  */
  69 #define PTHREAD_KEY_2NDLEVEL_SIZE       32
  70
  71 /* We need to address PTHREAD_KEYS_MAX key with PTHREAD_KEY_2NDLEVEL_SIZE
  72    keys in each subarray.  */
  73 #define PTHREAD_KEY_1STLEVEL_SIZE \
  74   ((PTHREAD_KEYS_MAX + PTHREAD_KEY_2NDLEVEL_SIZE - 1) \
  75    / PTHREAD_KEY_2NDLEVEL_SIZE)
  76
  77 typedef void (*destr_function)(void *);
  78
  79 struct pthread_key_struct {
  80   int in_use;                   /* already allocated? */
  81   destr_function destr;         /* destruction routine */
  82 };
  83
  84
  85 #define PTHREAD_START_ARGS_INITIALIZER(fct) \
  86   { (void *(*) (void *)) fct, NULL, {{0, }}, 0, { 0 } }
  87
  88 /* The type of thread descriptors */
  89
  90 typedef struct _pthread_descr_struct * pthread_descr;
  91
  92 /* Callback interface for removing the thread from waiting on an
  93    object if it is cancelled while waiting or about to wait.
  94    This hold a pointer to the object, and a pointer to a function
  95    which ``extricates'' the thread from its enqueued state.
  96    The function takes two arguments: pointer to the wait object,
  97    and a pointer to the thread. It returns 1 if an extrication
  98    actually occured, and hence the thread must also be signalled.
  99    It returns 0 if the thread had already been extricated. */
 100
 101 typedef struct _pthread_extricate_struct {
 102     void *pu_object;
 103     int (*pu_extricate_func)(void *, pthread_descr);
 104 } pthread_extricate_if;
 105
 106 /* Atomic counter made possible by compare_and_swap */
 107
 108 struct pthread_atomic {
 109   long p_count;
 110   int p_spinlock;
 111 };
 112
 113 /* Context info for read write locks. The pthread_rwlock_info structure
 114    is information about a lock that has been read-locked by the thread
 115    in whose list this structure appears. The pthread_rwlock_context
 116    is embedded in the thread context and contains a pointer to the
 117    head of the list of lock info structures, as well as a count of
 118    read locks that are untracked, because no info structure could be
 119    allocated for them. */
 120
 121 struct _pthread_rwlock_t;
 122
 123 typedef struct _pthread_rwlock_info {
 124   struct _pthread_rwlock_info *pr_next;
 125   struct _pthread_rwlock_t *pr_lock;
 126   int pr_lock_count;
 127 } pthread_readlock_info;
 128
 129 struct _pthread_descr_struct {
 130   union {
 131     struct {
 132       pthread_descr self;       /* Pointer to this structure */
 133     } data;
 134     void *__padding[16];
 135   } p_header;
 136   pthread_descr p_nextlive, p_prevlive;
 137                                 /* Double chaining of active threads */
 138   pthread_descr p_nextwaiting;  /* Next element in the queue holding the thr */
 139   pthread_descr p_nextlock;     /* can be on a queue and waiting on a lock */
 140   pthread_t p_tid;              /* Thread identifier */
 141   int p_pid;                    /* PID of Unix process */
 142   int p_priority;               /* Thread priority (== 0 if not realtime) */
 143   struct _pthread_fastlock * p_lock; /* Spinlock for synchronized accesses */
 144   int p_signal;                 /* last signal received */
 145   sigjmp_buf * p_signal_jmp;    /* where to siglongjmp on a signal or NULL */
 146   sigjmp_buf * p_cancel_jmp;    /* where to siglongjmp on a cancel or NULL */
 147   char p_terminated;            /* true if terminated e.g. by pthread_exit */
 148   char p_detached;              /* true if detached */
 149   char p_exited;                /* true if the assoc. process terminated */
 150   void * p_retval;              /* placeholder for return value */
 151   int p_retcode;                /* placeholder for return code */
 152   pthread_descr p_joining;      /* thread joining on that thread or NULL */
 153   struct _pthread_cleanup_buffer * p_cleanup; /* cleanup functions */
 154   char p_cancelstate;           /* cancellation state */
 155   char p_canceltype;            /* cancellation type (deferred/async) */
 156   char p_canceled;              /* cancellation request pending */
 157   int * p_errnop;               /* pointer to used errno variable */
 158   int p_errno;                  /* error returned by last system call */
 159   int * p_h_errnop;             /* pointer to used h_errno variable */
 160   int p_h_errno;                /* error returned by last netdb function */
 161   char * p_in_sighandler;       /* stack address of sighandler, or NULL */
 162   char p_sigwaiting;            /* true if a sigwait() is in progress */
 163   struct pthread_start_args p_start_args; /* arguments for thread creation */
 164   void ** p_specific[PTHREAD_KEY_1STLEVEL_SIZE]; /* thread-specific data */
 165   void * p_libc_specific[_LIBC_TSD_KEY_N]; /* thread-specific data for libc */
 166   int p_userstack;              /* nonzero if the user provided the stack */
 167   void *p_guardaddr;            /* address of guard area or NULL */
 168   size_t p_guardsize;           /* size of guard area */
 169   int p_nr;                     /* Index of descriptor in __pthread_handles */
 170   int p_report_events;          /* Nonzero if events must be reported.  */
 171   td_eventbuf_t p_eventbuf;     /* Data for event.  */
 172   struct pthread_atomic p_resume_count; /* number of times restart() was
 173                                            called on thread */
 174   char p_woken_by_cancel;       /* cancellation performed wakeup */
 175   char p_condvar_avail;         /* flag if conditional variable became avail */
 176   char p_sem_avail;             /* flag if semaphore became available */
 177   pthread_extricate_if *p_extricate; /* See above */
 178   pthread_readlock_info *p_readlock_list;  /* List of readlock info structs */
 179   pthread_readlock_info *p_readlock_free;  /* Free list of structs */
 180   int p_untracked_readlock_count;       /* Readlocks not tracked by list */
 181   struct __res_state *p_resp;   /* Pointer to resolver state */
 182   struct __res_state p_res;     /* per-thread resolver state */
 183   int p_inheritsched;           /* copied from the thread attribute */
 184 #if HP_TIMING_AVAIL
 185   hp_timing_t p_cpuclock_offset; /* Initial CPU clock for thread.  */
 186 #endif
 187   /* New elements must be added at the end.  */
 188 } __attribute__ ((aligned(32))); /* We need to align the structure so that
 189                                     doubles are aligned properly.  This is 8
 190                                     bytes on MIPS and 16 bytes on MIPS64.
 191                                     32 bytes might give better cache
 192                                     utilization.  */
 193
 194
 195 /* The type of thread handles. */
 196
 197 typedef struct pthread_handle_struct * pthread_handle;
 198
 199 struct pthread_handle_struct {
 200   struct _pthread_fastlock h_lock; /* Fast lock for sychronized access */
 201   pthread_descr h_descr;        /* Thread descriptor or NULL if invalid */
 202   char * h_bottom;              /* Lowest address in the stack thread */
 203 };
 204
 205 /* The type of messages sent to the thread manager thread */
 206
 207 struct pthread_request {
 208   pthread_descr req_thread;     /* Thread doing the request */
 209   enum {                        /* Request kind */
 210     REQ_CREATE, REQ_FREE, REQ_PROCESS_EXIT, REQ_MAIN_THREAD_EXIT,
 211     REQ_POST, REQ_DEBUG, REQ_KICK
 212   } req_kind;
 213   union {                       /* Arguments for request */
 214     struct {                    /* For REQ_CREATE: */
 215       const pthread_attr_t * attr; /* thread attributes */
 216       void * (*fn)(void *);     /*   start function */
 217       void * arg;               /*   argument to start function */
 218       sigset_t mask;            /*   signal mask */
 219     } create;
 220     struct {                    /* For REQ_FREE: */
 221       pthread_t thread_id;      /*   identifier of thread to free */
 222     } free;
 223     struct {                    /* For REQ_PROCESS_EXIT: */
 224       int code;                 /*   exit status */
 225     } exit;
 226     void * post;                /* For REQ_POST: the semaphore */
 227   } req_args;
 228 };
 229
 230
 231 /* Signals used for suspend/restart and for cancellation notification.  */
 232
 233 extern int __pthread_sig_restart;
 234 extern int __pthread_sig_cancel;
 235
 236 /* Signal used for interfacing with gdb */
 237
 238 extern int __pthread_sig_debug;
 239
 240 /* Global array of thread handles, used for validating a thread id
 241    and retrieving the corresponding thread descriptor. Also used for
 242    mapping the available stack segments. */
 243
 244 extern struct pthread_handle_struct __pthread_handles[PTHREAD_THREADS_MAX];
 245
 246 /* Descriptor of the initial thread */
 247
 248 extern struct _pthread_descr_struct __pthread_initial_thread;
 249
 250 /* Descriptor of the manager thread */
 251
 252 extern struct _pthread_descr_struct __pthread_manager_thread;
 253
 254 /* Descriptor of the main thread */
 255
 256 extern pthread_descr __pthread_main_thread;
 257
 258 /* Limit between the stack of the initial thread (above) and the
 259    stacks of other threads (below). Aligned on a STACK_SIZE boundary.
 260    Initially 0, meaning that the current thread is (by definition)
 261    the initial thread. */
 262
 263 extern char *__pthread_initial_thread_bos;
 264
 265 /* Indicate whether at least one thread has a user-defined stack (if 1),
 266    or all threads have stacks supplied by LinuxThreads (if 0). */
 267
 268 extern int __pthread_nonstandard_stacks;
 269
 270 /* File descriptor for sending requests to the thread manager.
 271    Initially -1, meaning that __pthread_initialize_manager must be called. */
 272
 273 extern int __pthread_manager_request;
 274
 275 /* Other end of the pipe for sending requests to the thread manager. */
 276
 277 extern int __pthread_manager_reader;
 278
 279 /* Limits of the thread manager stack. */
 280
 281 extern char *__pthread_manager_thread_bos;
 282 extern char *__pthread_manager_thread_tos;
 283
 284 #ifdef FLOATING_STACKS
 285 /* Maximum stack size.  */
 286 extern size_t __pthread_max_stacksize;
 287 #endif
 288
 289 /* Pending request for a process-wide exit */
 290
 291 extern int __pthread_exit_requested, __pthread_exit_code;
 292
 293 /* Set to 1 by gdb if we're debugging */
 294
 295 extern volatile int __pthread_threads_debug;
 296
 297 /* Globally enabled events.  */
 298 extern volatile td_thr_events_t __pthread_threads_events;
 299
 300 /* Pointer to descriptor of thread with last event.  */
 301 extern volatile pthread_descr __pthread_last_event;
 302
 303 /* Flag which tells whether we are executing on SMP kernel. */
 304 extern int __pthread_smp_kernel;
 305
 306 /* Return the handle corresponding to a thread id */
 307
 308 static inline pthread_handle thread_handle(pthread_t id)
 309 {
 310   return &__pthread_handles[id % PTHREAD_THREADS_MAX];
 311 }
 312
 313 /* Validate a thread handle. Must have acquired h->h_spinlock before. */
 314
 315 static inline int invalid_handle(pthread_handle h, pthread_t id)
 316 {
 317   return h->h_descr == NULL || h->h_descr->p_tid != id || h->h_descr->p_terminated;
 318 }
 319
 320 static inline int nonexisting_handle(pthread_handle h, pthread_t id)
 321 {
 322   return h->h_descr == NULL || h->h_descr->p_tid != id;
 323 }
 324
 325 /* Fill in defaults left unspecified by pt-machine.h.  */
 326
 327 /* We round up a value with page size. */
 328 #ifndef page_roundup
 329 #define page_roundup(v,p) ((((size_t) (v)) + (p) - 1) & ~((p) - 1))
 330 #endif
 331
 332 /* The page size we can get from the system.  This should likely not be
 333    changed by the machine file but, you never know.  */
 334 #ifndef PAGE_SIZE
 335 #define PAGE_SIZE  (sysconf (_SC_PAGE_SIZE))
 336 #endif
 337
 338 /* The max size of the thread stack segments.  If the default
 339    THREAD_SELF implementation is used, this must be a power of two and
 340    a multiple of PAGE_SIZE.  */
 341 #ifndef STACK_SIZE
 342 #define STACK_SIZE  (2 * 1024 * 1024)
 343 #endif
 344
 345 /* The initial size of the thread stack.  Must be a multiple of PAGE_SIZE.  */
 346 #ifndef INITIAL_STACK_SIZE
 347 #define INITIAL_STACK_SIZE  (4 * PAGE_SIZE)
 348 #endif
 349
 350 /* Size of the thread manager stack. The "- 32" avoids wasting space
 351    with some malloc() implementations. */
 352 #ifndef THREAD_MANAGER_STACK_SIZE
 353 #define THREAD_MANAGER_STACK_SIZE  (2 * PAGE_SIZE - 32)
 354 #endif
 355
 356 /* The base of the "array" of thread stacks.  The array will grow down from
 357    here.  Defaults to the calculated bottom of the initial application
 358    stack.  */
 359 #ifndef THREAD_STACK_START_ADDRESS
 360 #define THREAD_STACK_START_ADDRESS  __pthread_initial_thread_bos
 361 #endif
 362
 363 /* Get some notion of the current stack.  Need not be exactly the top
 364    of the stack, just something somewhere in the current frame.  */
 365 #ifndef CURRENT_STACK_FRAME
 366 #define CURRENT_STACK_FRAME  ({ char __csf; &__csf; })
 367 #endif
 368
 369 /* Recover thread descriptor for the current thread */
 370
 371 extern pthread_descr __pthread_find_self (void) __attribute__ ((const));
 372
 373 static inline pthread_descr thread_self (void) __attribute__ ((const));
 374 static inline pthread_descr thread_self (void)
 375 {
 376 #ifdef THREAD_SELF
 377   return THREAD_SELF;
 378 #else
 379   char *sp = CURRENT_STACK_FRAME;
 380   if (sp >= __pthread_initial_thread_bos)
 381     return &__pthread_initial_thread;
 382   else if (sp >= __pthread_manager_thread_bos
 383            && sp < __pthread_manager_thread_tos)
 384     return &__pthread_manager_thread;
 385   else if (__pthread_nonstandard_stacks)
 386     return __pthread_find_self();
 387   else
 388 #ifdef _STACK_GROWS_DOWN
 389     return (pthread_descr)(((unsigned long)sp | (STACK_SIZE-1))+1) - 1;
 390 #else
 391     return (pthread_descr)((unsigned long)sp &~ (STACK_SIZE-1));
 392 #endif
 393 #endif
 394 }
 395
 396 /* If MEMORY_BARRIER isn't defined in pt-machine.h, assume the architecture
 397    doesn't need a memory barrier instruction (e.g. Intel x86).  Some
 398    architectures distinguish between full, read and write barriers.  */
 399
 400 #ifndef MEMORY_BARRIER
 401 #define MEMORY_BARRIER()
 402 #endif
 403 #ifndef READ_MEMORY_BARRIER
 404 #define READ_MEMORY_BARRIER() MEMORY_BARRIER()
 405 #endif
 406 #ifndef WRITE_MEMORY_BARRIER
 407 #define WRITE_MEMORY_BARRIER() MEMORY_BARRIER()
 408 #endif
 409
 410 /* Max number of times we must spin on a spinlock calling sched_yield().
 411    After MAX_SPIN_COUNT iterations, we put the calling thread to sleep. */
 412
 413 #ifndef MAX_SPIN_COUNT
 414 #define MAX_SPIN_COUNT 50
 415 #endif
 416
 417 /* Max number of times the spinlock in the adaptive mutex implementation
 418    spins actively on SMP systems.  */
 419
 420 #ifndef MAX_ADAPTIVE_SPIN_COUNT
 421 #define MAX_ADAPTIVE_SPIN_COUNT 100
 422 #endif
 423
 424 /* Duration of sleep (in nanoseconds) when we can't acquire a spinlock
 425    after MAX_SPIN_COUNT iterations of sched_yield().
 426    With the 2.0 and 2.1 kernels, this MUST BE > 2ms.
 427    (Otherwise the kernel does busy-waiting for realtime threads,
 428     giving other threads no chance to run.) */
 429
 430 #ifndef SPIN_SLEEP_DURATION
 431 #define SPIN_SLEEP_DURATION 2000001
 432 #endif
 433
 434 /* Debugging */
 435
 436 #ifdef DEBUG
 437 #include <assert.h>
 438 #define ASSERT assert
 439 #define MSG __pthread_message
 440 #else
 441 #define ASSERT(x)
 442 #define MSG(msg,arg...)
 443 #endif
 444
 445 /* Internal global functions */
 446
 447 extern void __pthread_do_exit (void *retval, char *currentframe)
 448      __attribute__ ((__noreturn__));
 449 extern void __pthread_destroy_specifics (void);
 450 extern void __pthread_perform_cleanup (char *currentframe);
 451 extern void __pthread_init_max_stacksize (void);
 452 extern int __pthread_initialize_manager (void);
 453 extern void __pthread_message (char * fmt, ...);
 454 extern int __pthread_manager (void *reqfd);
 455 extern int __pthread_manager_event (void *reqfd);
 456 extern void __pthread_manager_sighandler (int sig);
 457 extern void __pthread_reset_main_thread (void);
 458 extern void __pthread_once_fork_prepare (void);
 459 extern void __pthread_once_fork_parent (void);
 460 extern void __pthread_once_fork_child (void);
 461 extern void __flockfilelist (void);
 462 extern void __funlockfilelist (void);
 463 extern void __fresetlockfiles (void);
 464 extern void __pthread_manager_adjust_prio (int thread_prio);
 465 extern void __pthread_initialize_minimal (void);
 466
 467 extern int __pthread_attr_setguardsize (pthread_attr_t *__attr,
 468                                         size_t __guardsize);
 469 extern int __pthread_attr_getguardsize (const pthread_attr_t *__attr,
 470                                         size_t *__guardsize);
 471 extern int __pthread_attr_setstackaddr (pthread_attr_t *__attr,
 472                                         void *__stackaddr);
 473 extern int __pthread_attr_getstackaddr (const pthread_attr_t *__attr,
 474                                         void **__stackaddr);
 475 extern int __pthread_attr_setstacksize (pthread_attr_t *__attr,
 476                                         size_t __stacksize);
 477 extern int __pthread_attr_getstacksize (const pthread_attr_t *__attr,
 478                                         size_t *__stacksize);
 479 extern int __pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
 480                                     size_t __stacksize);
 481 extern int __pthread_attr_getstack (const pthread_attr_t *__attr, void **__stackaddr,
 482                                     size_t *__stacksize);
 483 extern int __pthread_getconcurrency (void);
 484 extern int __pthread_setconcurrency (int __level);
 485 extern int __pthread_mutex_timedlock (pthread_mutex_t *__mutex,
 486                                       const struct timespec *__abstime);
 487 extern int __pthread_mutexattr_getpshared (const pthread_mutexattr_t *__attr,
 488                                            int *__pshared);
 489 extern int __pthread_mutexattr_setpshared (pthread_mutexattr_t *__attr,
 490                                            int __pshared);
 491 extern int __pthread_mutexattr_gettype (const pthread_mutexattr_t *__attr,
 492                                         int *__kind);
 493 extern void __pthread_kill_other_threads_np (void);
 494
 495 extern void __pthread_restart_old(pthread_descr th);
 496 extern void __pthread_suspend_old(pthread_descr self);
 497 extern int __pthread_timedsuspend_old(pthread_descr self, const struct timespec *abs);
 498
 499 extern void __pthread_restart_new(pthread_descr th);
 500 extern void __pthread_suspend_new(pthread_descr self);
 501 extern int __pthread_timedsuspend_new(pthread_descr self, const struct timespec *abs);
 502
 503 extern void __pthread_wait_for_restart_signal(pthread_descr self);
 504
 505 extern int __pthread_yield (void);
 506
 507 extern int __pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
 508                                          __const struct timespec *__restrict
 509                                          __abstime);
 510 extern int __pthread_rwlock_timedwrlock (pthread_rwlock_t *__restrict __rwlock,
 511                                          __const struct timespec *__restrict
 512                                          __abstime);
 513 extern int __pthread_rwlockattr_destroy (pthread_rwlockattr_t *__attr);
 514
 515 extern int __pthread_barrierattr_getpshared (__const pthread_barrierattr_t *
 516                                              __restrict __attr,
 517                                              int *__restrict __pshared);
 518
 519 extern int __pthread_spin_lock (pthread_spinlock_t *__lock);
 520 extern int __pthread_spin_trylock (pthread_spinlock_t *__lock);
 521 extern int __pthread_spin_unlock (pthread_spinlock_t *__lock);
 522 extern int __pthread_spin_init (pthread_spinlock_t *__lock, int __pshared);
 523 extern int __pthread_spin_destroy (pthread_spinlock_t *__lock);
 524
 525 extern int __pthread_clock_gettime (hp_timing_t freq, struct timespec *tp);
 526 extern void __pthread_clock_settime (hp_timing_t offset);
 527
 528
 529 /* Global pointers to old or new suspend functions */
 530
 531 extern void (*__pthread_restart)(pthread_descr);
 532 extern void (*__pthread_suspend)(pthread_descr);
 533 extern int (*__pthread_timedsuspend)(pthread_descr, const struct timespec *);
 534
 535 /* Prototypes for the function without cancelation support when the
 536    normal version has it.  */
 537 extern int __libc_close (int fd);
 538 extern int __libc_nanosleep (const struct timespec *requested_time,
 539                              struct timespec *remaining);
 540 /* Prototypes for some of the new semaphore functions.  */
 541 extern int __new_sem_post (sem_t * sem);
 542 extern int __new_sem_init (sem_t *__sem, int __pshared, unsigned int __value);
 543 extern int __new_sem_wait (sem_t *__sem);
 544 extern int __new_sem_trywait (sem_t *__sem);
 545 extern int __new_sem_getvalue (sem_t *__restrict __sem, int *__restrict __sval);
 546 extern int __new_sem_destroy (sem_t *__sem);
 547
 548 /* Prototypes for compatibility functions.  */
 549 extern int __pthread_attr_init_2_1 (pthread_attr_t *__attr);
 550 extern int __pthread_attr_init_2_0 (pthread_attr_t *__attr);
 551 extern int __pthread_create_2_1 (pthread_t *__restrict __thread,
 552                                  const pthread_attr_t *__attr,
 553                                  void *(*__start_routine) (void *),
 554                                  void *__restrict __arg);
 555 extern int __pthread_create_2_0 (pthread_t *__restrict thread,
 556                                  const pthread_attr_t *__attr,
 557                                  void *(*__start_routine) (void *),
 558                                  void *__restrict arg);
 559
 560 /* The functions called the signal events.  */
 561 extern void __linuxthreads_create_event (void);
 562 extern void __linuxthreads_death_event (void);
 563 extern void __linuxthreads_reap_event (void);
 564
 565 /* This function is called to initialize the pthread library.  */
 566 extern void __pthread_initialize (void);
 567
 568 #endif /* internals.h */