ext/threads/shared/shared.xs

   1 /*    shared.xs
   2  *
   3  *    Copyright (c) 2001-2002, Larry Wall
   4  *
   5  *    You may distribute under the terms of either the GNU General Public
   6  *    License or the Artistic License, as specified in the README file.
   7  *
   8  * "Hand any two wizards a piece of rope and they would instinctively pull in
   9  * opposite directions."
  10  *                         --Sourcery
  11  *
  12  * Contributed by Arthur Bergman arthur@contiller.se
  13  * pulled in the (an)other direction by Nick Ing-Simmons nick@ing-simmons.net
  14  */
  15
  16 #define PERL_NO_GET_CONTEXT
  17 #include "EXTERN.h"
  18 #include "perl.h"
  19 #include "XSUB.h"
  20
  21 #ifdef USE_ITHREADS
  22
  23 #define SHAREDSvPTR(a)      ((a)->sv)
  24
  25 /*
  26  * The shared things need an intepreter to live in ...
  27  */
  28 PerlInterpreter *PL_sharedsv_space;             /* The shared sv space */
  29 /* To access shared space we fake aTHX in this scope and thread's context */
  30
  31 /* bug #24255: we include ENTER+SAVETMPS/FREETMPS+LEAVE with
  32  * SHARED_CONTEXT/CALLER_CONTEXT macros, so that any mortals etc created
  33  * while in the shared interpreter context don't languish */
  34
  35 #define SHARED_CONTEXT \
  36     STMT_START {                                        \
  37         PERL_SET_CONTEXT((aTHX = PL_sharedsv_space));   \
  38         ENTER;                                          \
  39         SAVETMPS;                                       \
  40     } STMT_END
  41
  42 /* So we need a way to switch back to the caller's context... */
  43 /* So we declare _another_ copy of the aTHX variable ... */
  44 #define dTHXc PerlInterpreter *caller_perl = aTHX
  45
  46 /* and use it to switch back */
  47 #define CALLER_CONTEXT                                  \
  48     STMT_START {                                        \
  49         FREETMPS;                                       \
  50         LEAVE;                                          \
  51         PERL_SET_CONTEXT((aTHX = caller_perl));         \
  52     } STMT_END
  53
  54 /*
  55  * Only one thread at a time is allowed to mess with shared space.
  56  */
  57
  58 typedef struct
  59 {
  60  perl_mutex              mutex;
  61  PerlInterpreter        *owner;
  62  I32                     locks;
  63  perl_cond               cond;
  64 #ifdef DEBUG_LOCKS
  65  char *                  file;
  66  int                     line;
  67 #endif
  68 } recursive_lock_t;
  69
  70 recursive_lock_t PL_sharedsv_lock;       /* Mutex protecting the shared sv space */
  71
  72 void
  73 recursive_lock_init(pTHX_ recursive_lock_t *lock)
  74 {
  75     Zero(lock,1,recursive_lock_t);
  76     MUTEX_INIT(&lock->mutex);
  77     COND_INIT(&lock->cond);
  78 }
  79
  80 void
  81 recursive_lock_destroy(pTHX_ recursive_lock_t *lock)
  82 {
  83     MUTEX_DESTROY(&lock->mutex);
  84     COND_DESTROY(&lock->cond);
  85 }
  86
  87 void
  88 recursive_lock_release(pTHX_ recursive_lock_t *lock)
  89 {
  90     MUTEX_LOCK(&lock->mutex);
  91     if (lock->owner != aTHX) {
  92         MUTEX_UNLOCK(&lock->mutex);
  93     }
  94     else {
  95         if (--lock->locks == 0) {
  96             lock->owner = NULL;
  97             COND_SIGNAL(&lock->cond);
  98         }
  99     }
 100     MUTEX_UNLOCK(&lock->mutex);
 101 }
 102
 103 void
 104 recursive_lock_acquire(pTHX_ recursive_lock_t *lock,char *file,int line)
 105 {
 106     assert(aTHX);
 107     MUTEX_LOCK(&lock->mutex);
 108     if (lock->owner == aTHX) {
 109         lock->locks++;
 110     }
 111     else {
 112         while (lock->owner) {
 113 #ifdef DEBUG_LOCKS
 114             Perl_warn(aTHX_ " %p waiting - owned by %p %s:%d\n",
 115                       aTHX, lock->owner, lock->file, lock->line);
 116 #endif
 117             COND_WAIT(&lock->cond,&lock->mutex);
 118         }
 119         lock->locks = 1;
 120         lock->owner = aTHX;
 121 #ifdef DEBUG_LOCKS
 122         lock->file  = file;
 123         lock->line  = line;
 124 #endif
 125     }
 126     MUTEX_UNLOCK(&lock->mutex);
 127     SAVEDESTRUCTOR_X(recursive_lock_release,lock);
 128 }
 129
 130 #define ENTER_LOCK         STMT_START { \
 131                               ENTER; \
 132                               recursive_lock_acquire(aTHX_ &PL_sharedsv_lock, __FILE__, __LINE__);   \
 133                             } STMT_END
 134
 135 #define LEAVE_LOCK       LEAVE
 136
 137
 138 /* A common idiom is to acquire access and switch in ... */
 139 #define SHARED_EDIT         STMT_START {        \
 140                                 ENTER_LOCK;     \
 141                                 SHARED_CONTEXT; \
 142                             } STMT_END
 143
 144 /* then switch out and release access. */
 145 #define SHARED_RELEASE     STMT_START { \
 146                                 CALLER_CONTEXT; \
 147                                 LEAVE_LOCK;     \
 148                             } STMT_END
 149
 150
 151 /*
 152
 153   Shared SV
 154
 155   Shared SV is a structure for keeping the backend storage
 156   of shared svs.
 157
 158   Shared-ness really only needs the SV * - the rest is for locks.
 159   (Which suggests further space optimization ... )
 160
 161 */
 162
 163 typedef struct {
 164     SV                 *sv;             /* The actual SV - in shared space */
 165     recursive_lock_t    lock;
 166     perl_cond           user_cond;      /* For user-level conditions */
 167 } shared_sv;
 168
 169 /* The SV in shared-space has a back-pointer to the shared_sv
 170    struct associated with it PERL_MAGIC_ext.
 171
 172    The vtable used has just one entry - when the SV goes away
 173    we free the memory for the above.
 174
 175  */
 176
 177 int
 178 sharedsv_shared_mg_free(pTHX_ SV *sv, MAGIC *mg)
 179 {
 180     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 181     assert( aTHX == PL_sharedsv_space );
 182     if (shared) {
 183         recursive_lock_destroy(aTHX_ &shared->lock);
 184         COND_DESTROY(&shared->user_cond);
 185         PerlMemShared_free(shared);
 186         mg->mg_ptr = NULL;
 187     }
 188     return 0;
 189 }
 190
 191 MGVTBL sharedsv_shared_vtbl = {
 192  0,                             /* get */
 193  0,                             /* set */
 194  0,                             /* len */
 195  0,                             /* clear */
 196  sharedsv_shared_mg_free,       /* free */
 197  0,                             /* copy */
 198  0,                             /* dup */
 199 };
 200
 201 /* Access to shared things is heavily based on MAGIC - in mg.h/mg.c/sv.c sense */
 202
 203 /* In any thread that has access to a shared thing there is a "proxy"
 204    for it in its own space which has 'MAGIC' associated which accesses
 205    the shared thing.
 206  */
 207
 208 MGVTBL sharedsv_scalar_vtbl;    /* scalars have this vtable */
 209 MGVTBL sharedsv_array_vtbl;     /* hashes and arrays have this - like 'tie' */
 210 MGVTBL sharedsv_elem_vtbl;      /* elements of hashes and arrays have this
 211                                    _AS WELL AS_ the scalar magic */
 212
 213 /* The sharedsv_elem_vtbl associates the element with the array/hash and
 214    the sharedsv_scalar_vtbl associates it with the value
 215  */
 216
 217
 218 /* Accessor to convert threads::shared::tie objects back shared_sv * */
 219 shared_sv *
 220 SV_to_sharedsv(pTHX_ SV *sv)
 221 {
 222     shared_sv *shared = 0;
 223     if (SvROK(sv))
 224      {
 225       shared = INT2PTR(shared_sv *, SvIV(SvRV(sv)));
 226      }
 227     return shared;
 228 }
 229
 230 =for apidoc sharedsv_find
 231
 232 Given a private side SV tries to find if the SV has a shared backend,
 233 by looking for the magic.
 234
 235 =cut
 236
 237 shared_sv *
 238 Perl_sharedsv_find(pTHX_ SV *sv)
 239 {
 240     MAGIC *mg;
 241     if (SvTYPE(sv) >= SVt_PVMG) {
 242         switch(SvTYPE(sv)) {
 243         case SVt_PVAV:
 244         case SVt_PVHV:
 245             if ((mg = mg_find(sv, PERL_MAGIC_tied))
 246                 && mg->mg_virtual == &sharedsv_array_vtbl) {
 247                 return (shared_sv *) mg->mg_ptr;
 248             }
 249             break;
 250         default:
 251             /* This should work for elements as well as they
 252              * have scalar magic as well as their element magic
 253              */
 254             if ((mg = mg_find(sv, PERL_MAGIC_shared_scalar))
 255                 && mg->mg_virtual == &sharedsv_scalar_vtbl) {
 256                 return (shared_sv *) mg->mg_ptr;
 257             }
 258             break;
 259         }
 260     }
 261     /* Just for tidyness of API also handle tie objects */
 262     if (SvROK(sv) && sv_derived_from(sv, "threads::shared::tie")) {
 263         return SV_to_sharedsv(aTHX_ sv);
 264     }
 265     return NULL;
 266 }
 267
 268 /*
 269  *  Almost all the pain is in this routine.
 270  *
 271  */
 272
 273 shared_sv *
 274 Perl_sharedsv_associate(pTHX_ SV **psv, SV *ssv, shared_sv *data)
 275 {
 276     dTHXc;
 277     MAGIC *mg = 0;
 278     SV *sv    = (psv) ? *psv : Nullsv;
 279
 280     /* If we are asked for an private ops we need a thread */
 281     assert ( aTHX !=  PL_sharedsv_space );
 282
 283     /* To avoid need for recursive locks require caller to hold lock */
 284     assert ( PL_sharedsv_lock.owner == aTHX );
 285
 286     /* First try and get existing global data structure */
 287
 288     /* Try shared SV as 1st choice */
 289     if (!data && ssv && SvTYPE(ssv) >= SVt_PVMG) {
 290         if( (mg = mg_find(ssv, PERL_MAGIC_ext)) ){
 291             data = (shared_sv *) mg->mg_ptr;
 292         }
 293     }
 294
 295     /* Next see if private SV is associated with something */
 296     if (!data && sv) {
 297         data = Perl_sharedsv_find(aTHX_ sv);
 298     }
 299
 300     /* If neither of those then create a new one */
 301     if (!data) {
 302             SHARED_CONTEXT;
 303             if (!ssv) {
 304                 ssv = newSV(0);
 305                 SvREFCNT(ssv) = 0;
 306             }
 307             data = PerlMemShared_malloc(sizeof(shared_sv));
 308             Zero(data,1,shared_sv);
 309             SHAREDSvPTR(data) = ssv;
 310             /* Tag shared side SV with data pointer */
 311             sv_magicext(ssv, ssv, PERL_MAGIC_ext, &sharedsv_shared_vtbl,
 312                    (char *)data, 0);
 313             recursive_lock_init(aTHX_ &data->lock);
 314             COND_INIT(&data->user_cond);
 315             CALLER_CONTEXT;
 316     }
 317
 318     if (!ssv)
 319         ssv = SHAREDSvPTR(data);
 320     if (!SHAREDSvPTR(data))
 321         SHAREDSvPTR(data) = ssv;
 322
 323     /* If we know type upgrade shared side SV */
 324     if (sv && SvTYPE(ssv) < SvTYPE(sv)) {
 325         SHARED_CONTEXT;
 326         sv_upgrade(ssv, SvTYPE(*psv));
 327         if (SvTYPE(ssv) == SVt_PVAV)    /* #24061 */
 328             AvREAL_on(ssv);
 329         CALLER_CONTEXT;
 330     }
 331
 332     /* Now if requested allocate private SV */
 333     if (psv && !sv) {
 334         *psv = sv = newSV(0);
 335     }
 336
 337     /* Finally if private SV exists check and add magic */
 338     if (sv) {
 339         MAGIC *mg = 0;
 340         if (SvTYPE(sv) < SvTYPE(ssv)) {
 341             sv_upgrade(sv, SvTYPE(ssv));
 342         }
 343         switch(SvTYPE(sv)) {
 344         case SVt_PVAV:
 345         case SVt_PVHV:
 346             if (!(mg = mg_find(sv, PERL_MAGIC_tied))
 347                 || mg->mg_virtual != &sharedsv_array_vtbl
 348                 || (shared_sv *) mg->mg_ptr != data) {
 349                 SV *obj = newSV(0);
 350                 sv_setref_iv(obj, "threads::shared::tie",PTR2IV(data));
 351                 if (mg) {
 352                     sv_unmagic(sv, PERL_MAGIC_tied);
 353                 }
 354                 mg = sv_magicext(sv, obj, PERL_MAGIC_tied, &sharedsv_array_vtbl,
 355                                 (char *) data, 0);
 356                 mg->mg_flags |= (MGf_COPY|MGf_DUP);
 357                 SvREFCNT_inc(ssv);
 358                 SvREFCNT_dec(obj);
 359                 if(SvOBJECT(ssv)) {
 360                   STRLEN len;
 361                   char* stash_ptr = SvPV((SV*) SvSTASH(ssv), len);
 362                   HV* stash = gv_stashpvn(stash_ptr, len, TRUE);
 363                   SvOBJECT_on(sv);
 364                   SvSTASH(sv) = (HV*)SvREFCNT_inc(stash);
 365                 }
 366             }
 367             break;
 368
 369         default:
 370             if ((SvTYPE(sv) < SVt_PVMG)
 371                 || !(mg = mg_find(sv, PERL_MAGIC_shared_scalar))
 372                 || mg->mg_virtual != &sharedsv_scalar_vtbl
 373                 || (shared_sv *) mg->mg_ptr != data) {
 374                 if (mg) {
 375                     sv_unmagic(sv, PERL_MAGIC_shared_scalar);
 376                 }
 377                 mg = sv_magicext(sv, Nullsv, PERL_MAGIC_shared_scalar,
 378                                 &sharedsv_scalar_vtbl, (char *)data, 0);
 379                 mg->mg_flags |= (MGf_COPY|MGf_DUP);
 380                 SvREFCNT_inc(ssv);
 381             }
 382             break;
 383         }
 384         assert ( Perl_sharedsv_find(aTHX_ *psv) == data );
 385     }
 386     return data;
 387 }
 388
 389 void
 390 Perl_sharedsv_free(pTHX_ shared_sv *shared)
 391 {
 392     if (shared) {
 393         dTHXc;
 394         SHARED_EDIT;
 395         SvREFCNT_dec(SHAREDSvPTR(shared));
 396         SHARED_RELEASE;
 397     }
 398 }
 399
 400 void
 401 Perl_sharedsv_share(pTHX_ SV *sv)
 402 {
 403     switch(SvTYPE(sv)) {
 404     case SVt_PVGV:
 405         Perl_croak(aTHX_ "Cannot share globs yet");
 406         break;
 407
 408     case SVt_PVCV:
 409         Perl_croak(aTHX_ "Cannot share subs yet");
 410         break;
 411
 412     default:
 413         ENTER_LOCK;
 414         Perl_sharedsv_associate(aTHX_ &sv, 0, 0);
 415         LEAVE_LOCK;
 416         SvSETMAGIC(sv);
 417         break;
 418     }
 419 }
 420
 421 #if defined(WIN32) || defined(OS2)
 422 #  define ABS2RELMILLI(abs)        \
 423     do {                                \
 424         abs -= (double)time(NULL);      \
 425         if (abs > 0) { abs *= 1000; }   \
 426         else         { abs  = 0;    }   \
 427     } while (0)
 428 #endif /* WIN32 || OS2 */
 429
 430 bool
 431 Perl_sharedsv_cond_timedwait(perl_cond *cond, perl_mutex *mut, double abs)
 432 {
 433 #if defined(NETWARE) || defined(FAKE_THREADS) || defined(I_MACH_CTHREADS)
 434     Perl_croak_nocontext("cond_timedwait not supported on this platform");
 435 #else
 436 #  ifdef WIN32
 437     int got_it = 0;
 438
 439     ABS2RELMILLI(abs);
 440
 441     cond->waiters++;
 442     MUTEX_UNLOCK(mut);
 443     /* See comments in win32/win32thread.h COND_WAIT vis-a-vis race */
 444     switch (WaitForSingleObject(cond->sem, abs)) {
 445         case WAIT_OBJECT_0:   got_it = 1; break;
 446         case WAIT_TIMEOUT:                break;
 447         default:
 448             /* WAIT_FAILED? WAIT_ABANDONED? others? */
 449             Perl_croak_nocontext("panic: cond_timedwait (%ld)",GetLastError());
 450             break;
 451     }
 452     MUTEX_LOCK(mut);
 453     cond->waiters--;
 454     return got_it;
 455 #  else
 456 #    ifdef OS2
 457     int rc, got_it = 0;
 458     STRLEN n_a;
 459
 460     ABS2RELMILLI(abs);
 461
 462     if ((rc = DosResetEventSem(*cond,&n_a)) && (rc != ERROR_ALREADY_RESET))
 463         Perl_rc = rc, croak_with_os2error("panic: cond_timedwait-reset");
 464     MUTEX_UNLOCK(mut);
 465     if (CheckOSError(DosWaitEventSem(*cond,abs))
 466         && (rc != ERROR_INTERRUPT))
 467         croak_with_os2error("panic: cond_timedwait");
 468     if (rc == ERROR_INTERRUPT) errno = EINTR;
 469     MUTEX_LOCK(mut);
 470     return got_it;
 471 #    else         /* hope you're I_PTHREAD! */
 472     struct timespec ts;
 473     int got_it = 0;
 474
 475     ts.tv_sec = (long)abs;
 476     abs -= (NV)ts.tv_sec;
 477     ts.tv_nsec = (long)(abs * 1000000000.0);
 478
 479     switch (pthread_cond_timedwait(cond, mut, &ts)) {
 480         case 0:         got_it = 1; break;
 481         case ETIMEDOUT:             break;
 482         default:
 483             Perl_croak_nocontext("panic: cond_timedwait");
 484             break;
 485     }
 486     return got_it;
 487 #    endif /* OS2 */
 488 #  endif /* WIN32 */
 489 #endif /* NETWARE || FAKE_THREADS || I_MACH_CTHREADS */
 490 }
 491
 492 /* MAGIC (in mg.h sense) hooks */
 493
 494 int
 495 sharedsv_scalar_mg_get(pTHX_ SV *sv, MAGIC *mg)
 496 {
 497     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 498     assert(shared);
 499
 500     ENTER_LOCK;
 501     if (SHAREDSvPTR(shared)) {
 502         if (SvROK(SHAREDSvPTR(shared))) {
 503             SV *obj = Nullsv;
 504             Perl_sharedsv_associate(aTHX_ &obj, SvRV(SHAREDSvPTR(shared)), NULL);
 505             sv_setsv_nomg(sv, &PL_sv_undef);
 506             SvRV(sv) = obj;
 507             SvROK_on(sv);
 508
 509         }
 510         else {
 511             sv_setsv_nomg(sv, SHAREDSvPTR(shared));
 512         }
 513     }
 514     LEAVE_LOCK;
 515     return 0;
 516 }
 517
 518 void
 519 sharedsv_scalar_store(pTHX_ SV *sv, shared_sv *shared)
 520 {
 521     dTHXc;
 522     bool allowed = TRUE;
 523     if (SvROK(sv)) {
 524         shared_sv* target = Perl_sharedsv_find(aTHX_ SvRV(sv));
 525         if (target) {
 526             SV *tmp;
 527             SHARED_CONTEXT;
 528             tmp = newRV(SHAREDSvPTR(target));
 529             sv_setsv_nomg(SHAREDSvPTR(shared), tmp);
 530             SvREFCNT_dec(tmp);
 531             if(SvOBJECT(SvRV(sv))) {
 532               SV* fake_stash = newSVpv(HvNAME(SvSTASH(SvRV(sv))),0);
 533               SvOBJECT_on(SHAREDSvPTR(target));
 534               SvSTASH(SHAREDSvPTR(target)) = (HV*)fake_stash;
 535             }
 536             CALLER_CONTEXT;
 537         }
 538         else {
 539             allowed = FALSE;
 540         }
 541     }
 542     else {
 543         SvTEMP_off(sv);
 544         SHARED_CONTEXT;
 545         sv_setsv_nomg(SHAREDSvPTR(shared), sv);
 546         if(SvOBJECT(sv)) {
 547           SV* fake_stash = newSVpv(HvNAME(SvSTASH(sv)),0);
 548           SvOBJECT_on(SHAREDSvPTR(shared));
 549           SvSTASH(SHAREDSvPTR(shared)) = (HV*)fake_stash;
 550         }
 551         CALLER_CONTEXT;
 552     }
 553     if (!allowed) {
 554         Perl_croak(aTHX_ "Invalid value for shared scalar");
 555     }
 556 }
 557
 558 int
 559 sharedsv_scalar_mg_set(pTHX_ SV *sv, MAGIC *mg)
 560 {
 561     shared_sv *shared;
 562     ENTER_LOCK;
 563     /* We call associate to potentially upgrade shared side SV */
 564     shared = Perl_sharedsv_associate(aTHX_ &sv, Nullsv, (shared_sv *) mg->mg_ptr);
 565     assert(shared);
 566     sharedsv_scalar_store(aTHX_ sv, shared);
 567     LEAVE_LOCK;
 568     return 0;
 569 }
 570
 571 int
 572 sharedsv_scalar_mg_free(pTHX_ SV *sv, MAGIC *mg)
 573 {
 574     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 575 #if 0
 576     assert (SvREFCNT(SHAREDSvPTR(shared)) < 1000);
 577 #endif
 578     Perl_sharedsv_free(aTHX_ shared);
 579     return 0;
 580 }
 581
 582 int
 583 sharedsv_scalar_mg_clear(pTHX_ SV *sv, MAGIC *mg)
 584 {
 585     return 0;
 586 }
 587
 588 /*
 589  * Called during cloning of new threads
 590  */
 591 int
 592 sharedsv_scalar_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 593 {
 594     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 595     if (shared) {
 596         SvREFCNT_inc(SHAREDSvPTR(shared));
 597     }
 598     return 0;
 599 }
 600
 601 MGVTBL sharedsv_scalar_vtbl = {
 602  sharedsv_scalar_mg_get,        /* get */
 603  sharedsv_scalar_mg_set,        /* set */
 604  0,                             /* len */
 605  sharedsv_scalar_mg_clear,      /* clear */
 606  sharedsv_scalar_mg_free,       /* free */
 607  0,                             /* copy */
 608  sharedsv_scalar_mg_dup         /* dup */
 609 };
 610
 611 /* Now the arrays/hashes stuff */
 612 int
 613 sharedsv_elem_mg_FETCH(pTHX_ SV *sv, MAGIC *mg)
 614 {
 615     dTHXc;
 616     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 617     shared_sv *target = Perl_sharedsv_find(aTHX_ sv);
 618     SV** svp;
 619
 620     assert ( shared );
 621     assert ( SHAREDSvPTR(shared) );
 622
 623     ENTER_LOCK;
 624     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 625         assert ( mg->mg_ptr == 0 );
 626         SHARED_CONTEXT;
 627         svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 0);
 628     }
 629     else {
 630         char *key = mg->mg_ptr;
 631         STRLEN len = mg->mg_len;
 632         assert ( mg->mg_ptr != 0 );
 633         if (mg->mg_len == HEf_SVKEY) {
 634            key = SvPV((SV *) mg->mg_ptr, len);
 635         }
 636         SHARED_CONTEXT;
 637         svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 0);
 638     }
 639     CALLER_CONTEXT;
 640     if (svp) {
 641         /* Exists in the array */
 642         target = Perl_sharedsv_associate(aTHX_ &sv, *svp, target);
 643         sv_setsv(sv, *svp);
 644     }
 645     else {
 646         /* Not in the array */
 647         sv_setsv(sv, &PL_sv_undef);
 648     }
 649     LEAVE_LOCK;
 650     return 0;
 651 }
 652
 653 int
 654 sharedsv_elem_mg_STORE(pTHX_ SV *sv, MAGIC *mg)
 655 {
 656     dTHXc;
 657     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 658     shared_sv *target;
 659     SV **svp;
 660     /* Theory - SV itself is magically shared - and we have ordered the
 661        magic such that by the time we get here it has been stored
 662        to its shared counterpart
 663      */
 664     ENTER_LOCK;
 665     assert(shared);
 666     assert(SHAREDSvPTR(shared));
 667     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 668         assert ( mg->mg_ptr == 0 );
 669         SHARED_CONTEXT;
 670         svp = av_fetch((AV*) SHAREDSvPTR(shared), mg->mg_len, 1);
 671     }
 672     else {
 673         char *key = mg->mg_ptr;
 674         STRLEN len = mg->mg_len;
 675         assert ( mg->mg_ptr != 0 );
 676         if (mg->mg_len == HEf_SVKEY)
 677            key = SvPV((SV *) mg->mg_ptr, len);
 678         SHARED_CONTEXT;
 679         svp = hv_fetch((HV*) SHAREDSvPTR(shared), key, len, 1);
 680     }
 681     CALLER_CONTEXT;
 682     target = Perl_sharedsv_associate(aTHX_ &sv, *svp, 0);
 683     sharedsv_scalar_store(aTHX_ sv, target);
 684     LEAVE_LOCK;
 685     return 0;
 686 }
 687
 688 int
 689 sharedsv_elem_mg_DELETE(pTHX_ SV *sv, MAGIC *mg)
 690 {
 691     dTHXc;
 692     MAGIC *shmg;
 693     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 694     ENTER_LOCK;
 695     sharedsv_elem_mg_FETCH(aTHX_ sv, mg);
 696     if ((shmg = mg_find(sv, PERL_MAGIC_shared_scalar)))
 697         sharedsv_scalar_mg_get(aTHX_ sv, shmg);
 698     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 699         SHARED_CONTEXT;
 700         av_delete((AV*) SHAREDSvPTR(shared), mg->mg_len, G_DISCARD);
 701     }
 702     else {
 703         char *key = mg->mg_ptr;
 704         STRLEN len = mg->mg_len;
 705         assert ( mg->mg_ptr != 0 );
 706         if (mg->mg_len == HEf_SVKEY)
 707            key = SvPV((SV *) mg->mg_ptr, len);
 708         SHARED_CONTEXT;
 709         hv_delete((HV*) SHAREDSvPTR(shared), key, len, G_DISCARD);
 710     }
 711     CALLER_CONTEXT;
 712     LEAVE_LOCK;
 713     return 0;
 714 }
 715
 716 int
 717 sharedsv_elem_mg_free(pTHX_ SV *sv, MAGIC *mg)
 718 {
 719     Perl_sharedsv_free(aTHX_ SV_to_sharedsv(aTHX_ mg->mg_obj));
 720     return 0;
 721 }
 722
 723 int
 724 sharedsv_elem_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 725 {
 726     shared_sv *shared = SV_to_sharedsv(aTHX_ mg->mg_obj);
 727     SvREFCNT_inc(SHAREDSvPTR(shared));
 728     mg->mg_flags |= MGf_DUP;
 729     return 0;
 730 }
 731
 732 MGVTBL sharedsv_elem_vtbl = {
 733  sharedsv_elem_mg_FETCH,        /* get */
 734  sharedsv_elem_mg_STORE,        /* set */
 735  0,                             /* len */
 736  sharedsv_elem_mg_DELETE,       /* clear */
 737  sharedsv_elem_mg_free,         /* free */
 738  0,                             /* copy */
 739  sharedsv_elem_mg_dup           /* dup */
 740 };
 741
 742 U32
 743 sharedsv_array_mg_FETCHSIZE(pTHX_ SV *sv, MAGIC *mg)
 744 {
 745     dTHXc;
 746     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 747     U32 val;
 748     SHARED_EDIT;
 749     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 750         val = av_len((AV*) SHAREDSvPTR(shared));
 751     }
 752     else {
 753         /* not actually defined by tie API but ... */
 754         val = HvKEYS((HV*) SHAREDSvPTR(shared));
 755     }
 756     SHARED_RELEASE;
 757     return val;
 758 }
 759
 760 int
 761 sharedsv_array_mg_CLEAR(pTHX_ SV *sv, MAGIC *mg)
 762 {
 763     dTHXc;
 764     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 765     SHARED_EDIT;
 766     if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 767         av_clear((AV*) SHAREDSvPTR(shared));
 768     }
 769     else {
 770         hv_clear((HV*) SHAREDSvPTR(shared));
 771     }
 772     SHARED_RELEASE;
 773     return 0;
 774 }
 775
 776 int
 777 sharedsv_array_mg_free(pTHX_ SV *sv, MAGIC *mg)
 778 {
 779     Perl_sharedsv_free(aTHX_ (shared_sv *) mg->mg_ptr);
 780     return 0;
 781 }
 782
 783 /*
 784  * This is called when perl is about to access an element of
 785  * the array -
 786  */
 787 int
 788 sharedsv_array_mg_copy(pTHX_ SV *sv, MAGIC* mg,
 789                        SV *nsv, const char *name, int namlen)
 790 {
 791     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 792     MAGIC *nmg = sv_magicext(nsv,mg->mg_obj,
 793                             toLOWER(mg->mg_type),&sharedsv_elem_vtbl,
 794                             name, namlen);
 795     ENTER_LOCK;
 796     SvREFCNT_inc(SHAREDSvPTR(shared));
 797     LEAVE_LOCK;
 798     nmg->mg_flags |= MGf_DUP;
 799     return 1;
 800 }
 801
 802 int
 803 sharedsv_array_mg_dup(pTHX_ MAGIC *mg, CLONE_PARAMS *param)
 804 {
 805     shared_sv *shared = (shared_sv *) mg->mg_ptr;
 806     SvREFCNT_inc(SHAREDSvPTR(shared));
 807     mg->mg_flags |= MGf_DUP;
 808     return 0;
 809 }
 810
 811 MGVTBL sharedsv_array_vtbl = {
 812  0,                             /* get */
 813  0,                             /* set */
 814  sharedsv_array_mg_FETCHSIZE,   /* len */
 815  sharedsv_array_mg_CLEAR,       /* clear */
 816  sharedsv_array_mg_free,        /* free */
 817  sharedsv_array_mg_copy,        /* copy */
 818  sharedsv_array_mg_dup          /* dup */
 819 };
 820
 821 =for apidoc sharedsv_unlock
 822
 823 Recursively unlocks a shared sv.
 824
 825 =cut
 826
 827 void
 828 Perl_sharedsv_unlock(pTHX_ shared_sv* ssv)
 829 {
 830     recursive_lock_release(aTHX_ &ssv->lock);
 831 }
 832
 833 =for apidoc sharedsv_lock
 834
 835 Recursive locks on a sharedsv.
 836 Locks are dynamically scoped at the level of the first lock.
 837
 838 =cut
 839
 840 void
 841 Perl_sharedsv_lock(pTHX_ shared_sv* ssv)
 842 {
 843     if (!ssv)
 844         return;
 845     recursive_lock_acquire(aTHX_ &ssv->lock, __FILE__, __LINE__);
 846 }
 847
 848 /* handles calls from lock() builtin via PL_lockhook */
 849
 850 void
 851 Perl_sharedsv_locksv(pTHX_ SV *sv)
 852 {
 853     shared_sv* shared;
 854
 855     if(SvROK(sv))
 856         sv = SvRV(sv);
 857     shared = Perl_sharedsv_find(aTHX_ sv);
 858     if(!shared)
 859        croak("lock can only be used on shared values");
 860     Perl_sharedsv_lock(aTHX_ shared);
 861 }
 862
 863 =head1 Shared SV Functions
 864
 865 =for apidoc sharedsv_init
 866
 867 Saves a space for keeping SVs wider than an interpreter,
 868
 869 =cut
 870
 871 void
 872 Perl_sharedsv_init(pTHX)
 873 {
 874   dTHXc;
 875   /* This pair leaves us in shared context ... */
 876   PL_sharedsv_space = perl_alloc();
 877   perl_construct(PL_sharedsv_space);
 878   CALLER_CONTEXT;
 879   recursive_lock_init(aTHX_ &PL_sharedsv_lock);
 880   PL_lockhook = &Perl_sharedsv_locksv;
 881   PL_sharehook = &Perl_sharedsv_share;
 882 }
 883
 884 #endif /* USE_ITHREADS */
 885
 886 MODULE = threads::shared        PACKAGE = threads::shared::tie
 887
 888 PROTOTYPES: DISABLE
 889
 890 #ifdef USE_ITHREADS
 891
 892 void
 893 PUSH(shared_sv *shared, ...)
 894 CODE:
 895         dTHXc;
 896         int i;
 897         for(i = 1; i < items; i++) {
 898             SV* tmp = newSVsv(ST(i));
 899             shared_sv *target;
 900             ENTER_LOCK;
 901             target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
 902             sharedsv_scalar_store(aTHX_ tmp, target);
 903             SHARED_CONTEXT;
 904             av_push((AV*) SHAREDSvPTR(shared), SHAREDSvPTR(target));
 905             SvREFCNT_inc(SHAREDSvPTR(target));
 906             SHARED_RELEASE;
 907             SvREFCNT_dec(tmp);
 908         }
 909
 910 void
 911 UNSHIFT(shared_sv *shared, ...)
 912 CODE:
 913         dTHXc;
 914         int i;
 915         ENTER_LOCK;
 916         SHARED_CONTEXT;
 917         av_unshift((AV*)SHAREDSvPTR(shared), items - 1);
 918         CALLER_CONTEXT;
 919         for(i = 1; i < items; i++) {
 920             SV* tmp = newSVsv(ST(i));
 921             shared_sv *target = Perl_sharedsv_associate(aTHX_ &tmp, Nullsv, 0);
 922             sharedsv_scalar_store(aTHX_ tmp, target);
 923             SHARED_CONTEXT;
 924             av_store((AV*) SHAREDSvPTR(shared), i - 1, SHAREDSvPTR(target));
 925             SvREFCNT_inc(SHAREDSvPTR(target));
 926             CALLER_CONTEXT;
 927             SvREFCNT_dec(tmp);
 928         }
 929         LEAVE_LOCK;
 930
 931 void
 932 POP(shared_sv *shared)
 933 CODE:
 934         dTHXc;
 935         SV* sv;
 936         ENTER_LOCK;
 937         SHARED_CONTEXT;
 938         sv = av_pop((AV*)SHAREDSvPTR(shared));
 939         CALLER_CONTEXT;
 940         ST(0) = sv_newmortal();
 941         Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
 942         SvREFCNT_dec(sv);
 943         LEAVE_LOCK;
 944         XSRETURN(1);
 945
 946 void
 947 SHIFT(shared_sv *shared)
 948 CODE:
 949         dTHXc;
 950         SV* sv;
 951         ENTER_LOCK;
 952         SHARED_CONTEXT;
 953         sv = av_shift((AV*)SHAREDSvPTR(shared));
 954         CALLER_CONTEXT;
 955         ST(0) = sv_newmortal();
 956         Perl_sharedsv_associate(aTHX_ &ST(0), sv, 0);
 957         SvREFCNT_dec(sv);
 958         LEAVE_LOCK;
 959         XSRETURN(1);
 960
 961 void
 962 EXTEND(shared_sv *shared, IV count)
 963 CODE:
 964         dTHXc;
 965         SHARED_EDIT;
 966         av_extend((AV*)SHAREDSvPTR(shared), count);
 967         SHARED_RELEASE;
 968
 969 void
 970 STORESIZE(shared_sv *shared,IV count)
 971 CODE:
 972         dTHXc;
 973         SHARED_EDIT;
 974         av_fill((AV*) SHAREDSvPTR(shared), count);
 975         SHARED_RELEASE;
 976
 977
 978
 979
 980 void
 981 EXISTS(shared_sv *shared, SV *index)
 982 CODE:
 983         dTHXc;
 984         bool exists;
 985         if (SvTYPE(SHAREDSvPTR(shared)) == SVt_PVAV) {
 986             SHARED_EDIT;
 987             exists = av_exists((AV*) SHAREDSvPTR(shared), SvIV(index));
 988         }
 989         else {
 990             STRLEN len;
 991             char *key = SvPV(index,len);
 992             SHARED_EDIT;
 993             exists = hv_exists((HV*) SHAREDSvPTR(shared), key, len);
 994         }
 995         SHARED_RELEASE;
 996         ST(0) = (exists) ? &PL_sv_yes : &PL_sv_no;
 997         XSRETURN(1);
 998
 999
1000 void
1001 FIRSTKEY(shared_sv *shared)
1002 CODE:
1003         dTHXc;
1004         char* key = NULL;
1005         I32 len = 0;
1006         HE* entry;
1007         ENTER_LOCK;
1008         SHARED_CONTEXT;
1009         hv_iterinit((HV*) SHAREDSvPTR(shared));
1010         entry = hv_iternext((HV*) SHAREDSvPTR(shared));
1011         if (entry) {
1012                 key = hv_iterkey(entry,&len);
1013                 CALLER_CONTEXT;
1014                 ST(0) = sv_2mortal(newSVpv(key, len));
1015         } else {
1016              CALLER_CONTEXT;
1017              ST(0) = &PL_sv_undef;
1018         }
1019         LEAVE_LOCK;
1020         XSRETURN(1);
1021
1022 void
1023 NEXTKEY(shared_sv *shared, SV *oldkey)
1024 CODE:
1025         dTHXc;
1026         char* key = NULL;
1027         I32 len = 0;
1028         HE* entry;
1029         ENTER_LOCK;
1030         SHARED_CONTEXT;
1031         entry = hv_iternext((HV*) SHAREDSvPTR(shared));
1032         if (entry) {
1033                 key = hv_iterkey(entry,&len);
1034                 CALLER_CONTEXT;
1035                 ST(0) = sv_2mortal(newSVpv(key, len));
1036         } else {
1037              CALLER_CONTEXT;
1038              ST(0) = &PL_sv_undef;
1039         }
1040         LEAVE_LOCK;
1041         XSRETURN(1);
1042
1043 MODULE = threads::shared                PACKAGE = threads::shared
1044
1045 PROTOTYPES: ENABLE
1046
1047 void
1048 _id(SV *ref)
1049         PROTOTYPE: \[$@%]
1050 CODE:
1051         shared_sv *shared;
1052         ref = SvRV(ref);
1053         if(SvROK(ref))
1054             ref = SvRV(ref);
1055         if( (shared = Perl_sharedsv_find(aTHX_ ref)) ){
1056             ST(0) = sv_2mortal(newSViv(PTR2IV(shared)));
1057             XSRETURN(1);
1058         }
1059         XSRETURN_UNDEF;
1060
1061
1062 void
1063 _refcnt(SV *ref)
1064         PROTOTYPE: \[$@%]
1065 CODE:
1066         shared_sv *shared;
1067         ref = SvRV(ref);
1068         if(SvROK(ref))
1069             ref = SvRV(ref);
1070         if( (shared = Perl_sharedsv_find(aTHX_ ref)) ){
1071           if (SHAREDSvPTR(shared)) {
1072             ST(0) = sv_2mortal(newSViv(SvREFCNT(SHAREDSvPTR(shared))));
1073             XSRETURN(1);
1074           }
1075           else {
1076              Perl_warn(aTHX_ "%" SVf " s=%p has no shared SV",ST(0),shared);
1077           }
1078         }
1079         else {
1080              Perl_warn(aTHX_ "%" SVf " is not shared",ST(0));
1081         }
1082         XSRETURN_UNDEF;
1083
1084 SV*
1085 share(SV *ref)
1086         PROTOTYPE: \[$@%]
1087         CODE:
1088         if(!SvROK(ref))
1089             Perl_croak(aTHX_ "Argument to share needs to be passed as ref");
1090         ref = SvRV(ref);
1091         if(SvROK(ref))
1092             ref = SvRV(ref);
1093         Perl_sharedsv_share(aTHX_ ref);
1094         RETVAL = newRV(ref);
1095         OUTPUT:
1096         RETVAL
1097
1098 void
1099 lock_enabled(SV *ref)
1100         PROTOTYPE: \[$@%]
1101         CODE:
1102         shared_sv* shared;
1103         if(!SvROK(ref))
1104             Perl_croak(aTHX_ "Argument to lock needs to be passed as ref");
1105         ref = SvRV(ref);
1106         if(SvROK(ref))
1107             ref = SvRV(ref);
1108         shared = Perl_sharedsv_find(aTHX_ ref);
1109         if(!shared)
1110            croak("lock can only be used on shared values");
1111         Perl_sharedsv_lock(aTHX_ shared);
1112
1113 void
1114 cond_wait_enabled(SV *ref_cond, SV *ref_lock = 0)
1115         PROTOTYPE: \[$@%];\[$@%]
1116         PREINIT:
1117         shared_sv* shared;
1118         perl_cond* user_condition;
1119         int locks;
1120         int same = 0;
1121
1122         CODE:
1123         if (!ref_lock || ref_lock == ref_cond) same = 1;
1124
1125         if(!SvROK(ref_cond))
1126             Perl_croak(aTHX_ "Argument to cond_wait needs to be passed as ref");
1127         ref_cond = SvRV(ref_cond);
1128         if(SvROK(ref_cond))
1129             ref_cond = SvRV(ref_cond);
1130         shared = Perl_sharedsv_find(aTHX_ ref_cond);
1131         if(!shared)
1132             croak("cond_wait can only be used on shared values");
1133
1134         user_condition = &shared->user_cond;
1135         if (! same) {
1136             if (!SvROK(ref_lock))
1137                 Perl_croak(aTHX_ "cond_wait lock needs to be passed as ref");
1138             ref_lock = SvRV(ref_lock);
1139             if (SvROK(ref_lock)) ref_lock = SvRV(ref_lock);
1140             shared = Perl_sharedsv_find(aTHX_ ref_lock);
1141             if (!shared)
1142                 croak("cond_wait lock must be a shared value");
1143         }
1144         if(shared->lock.owner != aTHX)
1145             croak("You need a lock before you can cond_wait");
1146         /* Stealing the members of the lock object worries me - NI-S */
1147         MUTEX_LOCK(&shared->lock.mutex);
1148         shared->lock.owner = NULL;
1149         locks = shared->lock.locks;
1150         shared->lock.locks = 0;
1151
1152         /* since we are releasing the lock here we need to tell other
1153         people that is ok to go ahead and use it */
1154         COND_SIGNAL(&shared->lock.cond);
1155         COND_WAIT(user_condition, &shared->lock.mutex);
1156         while(shared->lock.owner != NULL) {
1157             /* OK -- must reacquire the lock */
1158             COND_WAIT(&shared->lock.cond, &shared->lock.mutex);
1159         }
1160         shared->lock.owner = aTHX;
1161         shared->lock.locks = locks;
1162         MUTEX_UNLOCK(&shared->lock.mutex);
1163
1164 int
1165 cond_timedwait_enabled(SV *ref_cond, double abs, SV *ref_lock = 0)
1166         PROTOTYPE: \[$@%]$;\[$@%]
1167         PREINIT:
1168         shared_sv* shared;
1169         perl_cond* user_condition;
1170         int locks;
1171         int same = 0;
1172
1173         CODE:
1174         if (!ref_lock || ref_cond == ref_lock) same = 1;
1175
1176         if(!SvROK(ref_cond))
1177             Perl_croak(aTHX_ "Argument to cond_timedwait needs to be passed as ref");
1178         ref_cond = SvRV(ref_cond);
1179         if(SvROK(ref_cond))
1180             ref_cond = SvRV(ref_cond);
1181         shared = Perl_sharedsv_find(aTHX_ ref_cond);
1182         if(!shared)
1183             croak("cond_timedwait can only be used on shared values");
1184
1185         user_condition = &shared->user_cond;
1186         if (! same) {
1187             if (!SvROK(ref_lock))
1188                 Perl_croak(aTHX_ "cond_timedwait lock needs to be passed as ref");
1189             ref_lock = SvRV(ref_lock);
1190             if (SvROK(ref_lock)) ref_lock = SvRV(ref_lock);
1191             shared = Perl_sharedsv_find(aTHX_ ref_lock);
1192             if (!shared)
1193                 croak("cond_timedwait lock must be a shared value");
1194         }
1195         if(shared->lock.owner != aTHX)
1196             croak("You need a lock before you can cond_wait");
1197
1198         MUTEX_LOCK(&shared->lock.mutex);
1199         shared->lock.owner = NULL;
1200         locks = shared->lock.locks;
1201         shared->lock.locks = 0;
1202         /* since we are releasing the lock here we need to tell other
1203         people that is ok to go ahead and use it */
1204         COND_SIGNAL(&shared->lock.cond);
1205         RETVAL = Perl_sharedsv_cond_timedwait(user_condition, &shared->lock.mutex, abs);
1206         while (shared->lock.owner != NULL) {
1207             /* OK -- must reacquire the lock... */
1208             COND_WAIT(&shared->lock.cond, &shared->lock.mutex);
1209         }
1210         shared->lock.owner = aTHX;
1211         shared->lock.locks = locks;
1212         MUTEX_UNLOCK(&shared->lock.mutex);
1213
1214         if (RETVAL == 0)
1215             XSRETURN_UNDEF;
1216         OUTPUT:
1217         RETVAL
1218
1219 void
1220 cond_signal_enabled(SV *ref)
1221         PROTOTYPE: \[$@%]
1222         CODE:
1223         shared_sv* shared;
1224         if(!SvROK(ref))
1225             Perl_croak(aTHX_ "Argument to cond_signal needs to be passed as ref");
1226         ref = SvRV(ref);
1227         if(SvROK(ref))
1228             ref = SvRV(ref);
1229         shared = Perl_sharedsv_find(aTHX_ ref);
1230         if (ckWARN(WARN_THREADS) && shared->lock.owner != aTHX)
1231             Perl_warner(aTHX_ packWARN(WARN_THREADS),
1232                             "cond_signal() called on unlocked variable");
1233         if(!shared)
1234             croak("cond_signal can only be used on shared values");
1235         COND_SIGNAL(&shared->user_cond);
1236
1237 void
1238 cond_broadcast_enabled(SV *ref)
1239         PROTOTYPE: \[$@%]
1240         CODE:
1241         shared_sv* shared;
1242         if(!SvROK(ref))
1243             Perl_croak(aTHX_ "Argument to cond_broadcast needs to be passed as ref");
1244         ref = SvRV(ref);
1245         if(SvROK(ref))
1246             ref = SvRV(ref);
1247         shared = Perl_sharedsv_find(aTHX_ ref);
1248         if(!shared)
1249             croak("cond_broadcast can only be used on shared values");
1250         if (ckWARN(WARN_THREADS) && shared->lock.owner != aTHX)
1251             Perl_warner(aTHX_ packWARN(WARN_THREADS),
1252                             "cond_broadcast() called on unlocked variable");
1253         COND_BROADCAST(&shared->user_cond);
1254
1255
1256 SV*
1257 bless(SV* ref, ...);
1258         PROTOTYPE: $;$
1259         CODE:
1260         {
1261           HV* stash;
1262           shared_sv* shared;
1263           if (items == 1)
1264             stash = CopSTASH(PL_curcop);
1265           else {
1266             SV* ssv = ST(1);
1267             STRLEN len;
1268             char *ptr;
1269
1270             if (ssv && !SvGMAGICAL(ssv) && !SvAMAGIC(ssv) && SvROK(ssv))
1271               Perl_croak(aTHX_ "Attempt to bless into a reference");
1272             ptr = SvPV(ssv,len);
1273             if (ckWARN(WARN_MISC) && len == 0)
1274               Perl_warner(aTHX_ packWARN(WARN_MISC),
1275                           "Explicit blessing to '' (assuming package main)");
1276             stash = gv_stashpvn(ptr, len, TRUE);
1277           }
1278           SvREFCNT_inc(ref);
1279           (void)sv_bless(ref, stash);
1280           RETVAL = ref;
1281           shared = Perl_sharedsv_find(aTHX_ ref);
1282           if(shared) {
1283             dTHXc;
1284             ENTER_LOCK;
1285             SHARED_CONTEXT;
1286             {
1287               SV* fake_stash = newSVpv(HvNAME(stash),0);
1288               (void)sv_bless(SHAREDSvPTR(shared),(HV*)fake_stash);
1289             }
1290             CALLER_CONTEXT;
1291             LEAVE_LOCK;
1292           }
1293         }
1294         OUTPUT:
1295         RETVAL
1296
1297 #endif /* USE_ITHREADS */
1298
1299 BOOT:
1300 {
1301 #ifdef USE_ITHREADS
1302      Perl_sharedsv_init(aTHX);
1303 #endif /* USE_ITHREADS */
1304 }
1305
1306
1307