1 /* Copyright (C) 2002-2017 Free Software Foundation, Inc.
2 Contributed by Andy Vaught
3 F2003 I/O support contributed by Jerry DeLisle
5 This file is part of the GNU Fortran runtime library (libgfortran).
7 Libgfortran is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 Libgfortran is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
35 UNIT_LOCK is a master lock, protecting UNIT_ROOT tree and UNIT_CACHE.
36 Concurrent use of different units should be supported, so
37 each unit has its own lock, LOCK.
38 Open should be atomic with its reopening of units and list_read.c
39 in several places needs find_unit another unit while holding stdin
40 unit's lock, so it must be possible to acquire UNIT_LOCK while holding
41 some unit's lock. Therefore to avoid deadlocks, it is forbidden
42 to acquire unit's private locks while holding UNIT_LOCK, except
43 for freshly created units (where no other thread can get at their
44 address yet) or when using just trylock rather than lock operation.
45 In addition to unit's private lock each unit has a WAITERS counter
46 and CLOSED flag. WAITERS counter must be either only
47 atomically incremented/decremented in all places (if atomic builtins
48 are supported), or protected by UNIT_LOCK in all places (otherwise).
49 CLOSED flag must be always protected by unit's LOCK.
50 After finding a unit in UNIT_CACHE or UNIT_ROOT with UNIT_LOCK held,
51 WAITERS must be incremented to avoid concurrent close from freeing
52 the unit between unlocking UNIT_LOCK and acquiring unit's LOCK.
53 Unit freeing is always done under UNIT_LOCK. If close_unit sees any
54 WAITERS, it doesn't free the unit but instead sets the CLOSED flag
55 and the thread that decrements WAITERS to zero while CLOSED flag is
56 set is responsible for freeing it (while holding UNIT_LOCK).
57 flush_all_units operation is iterating over the unit tree with
58 increasing UNIT_NUMBER while holding UNIT_LOCK and attempting to
59 flush each unit (and therefore needs the unit's LOCK held as well).
60 To avoid deadlocks, it just trylocks the LOCK and if unsuccessful,
61 remembers the current unit's UNIT_NUMBER, unlocks UNIT_LOCK, acquires
62 unit's LOCK and after flushing reacquires UNIT_LOCK and restarts with
63 the smallest UNIT_NUMBER above the last one flushed.
65 If find_unit/find_or_create_unit/find_file/get_unit routines return
66 non-NULL, the returned unit has its private lock locked and when the
67 caller is done with it, it must call either unlock_unit or close_unit
68 on it. unlock_unit or close_unit must be always called only with the
73 /* Table of allocated newunit values. A simple solution would be to
74 map OS file descriptors (fd's) to unit numbers, e.g. with newunit =
75 -fd - 2, however that doesn't work since Fortran allows an existing
76 unit number to be reassociated with a new file. Thus the simple
77 approach may lead to a situation where we'd try to assign a
78 (negative) unit number which already exists. Hence we must keep
79 track of allocated newunit values ourselves. This is the purpose of
80 the newunits array. The indices map to newunit values as newunit =
81 -index + NEWUNIT_FIRST. E.g. newunits[0] having the value true
82 means that a unit with number NEWUNIT_FIRST exists. Similar to
83 POSIX file descriptors, we always allocate the lowest (in absolute
84 value) available unit number.
86 static bool *newunits
;
87 static int newunit_size
; /* Total number of elements in the newunits array. */
88 /* Low water indicator for the newunits array. Below the LWI all the
89 units are allocated, above and equal to the LWI there may be both
90 allocated and free units. */
91 static int newunit_lwi
;
92 static void newunit_free (int);
94 /* Unit numbers assigned with NEWUNIT start from here. */
95 #define NEWUNIT_START -10
98 static gfc_unit
*unit_cache
[CACHE_SIZE
];
99 gfc_offset max_offset
;
101 #ifdef __GTHREAD_MUTEX_INIT
102 __gthread_mutex_t unit_lock
= __GTHREAD_MUTEX_INIT
;
104 __gthread_mutex_t unit_lock
;
107 /* We use these filenames for error reporting. */
109 static char stdin_name
[] = "stdin";
110 static char stdout_name
[] = "stdout";
111 static char stderr_name
[] = "stderr";
114 #ifdef HAVE_NEWLOCALE
117 /* If we don't have POSIX 2008 per-thread locales, we need to use the
118 traditional setlocale(). To prevent multiple concurrent threads
119 doing formatted I/O from messing up the locale, we need to store a
120 global old_locale, and a counter keeping track of how many threads
121 are currently doing formatted I/O. The first thread saves the old
122 locale, and the last one restores it. */
125 #ifdef __GTHREAD_MUTEX_INIT
126 __gthread_mutex_t old_locale_lock
= __GTHREAD_MUTEX_INIT
;
128 __gthread_mutex_t old_locale_lock
;
133 /* This implementation is based on Stefan Nilsson's article in the
134 July 1997 Doctor Dobb's Journal, "Treaps in Java". */
136 /* pseudo_random()-- Simple linear congruential pseudorandom number
137 generator. The period of this generator is 44071, which is plenty
143 static int x0
= 5341;
145 x0
= (22611 * x0
+ 10) % 44071;
150 /* rotate_left()-- Rotate the treap left */
153 rotate_left (gfc_unit
*t
)
158 t
->right
= t
->right
->left
;
165 /* rotate_right()-- Rotate the treap right */
168 rotate_right (gfc_unit
*t
)
173 t
->left
= t
->left
->right
;
181 compare (int a
, int b
)
192 /* insert()-- Recursive insertion function. Returns the updated treap. */
195 insert (gfc_unit
*new, gfc_unit
*t
)
202 c
= compare (new->unit_number
, t
->unit_number
);
206 t
->left
= insert (new, t
->left
);
207 if (t
->priority
< t
->left
->priority
)
208 t
= rotate_right (t
);
213 t
->right
= insert (new, t
->right
);
214 if (t
->priority
< t
->right
->priority
)
219 internal_error (NULL
, "insert(): Duplicate key found!");
225 /* insert_unit()-- Create a new node, insert it into the treap. */
230 gfc_unit
*u
= xcalloc (1, sizeof (gfc_unit
));
232 #ifdef __GTHREAD_MUTEX_INIT
234 __gthread_mutex_t tmp
= __GTHREAD_MUTEX_INIT
;
238 __GTHREAD_MUTEX_INIT_FUNCTION (&u
->lock
);
240 __gthread_mutex_lock (&u
->lock
);
241 u
->priority
= pseudo_random ();
242 unit_root
= insert (u
, unit_root
);
247 /* destroy_unit_mutex()-- Destroy the mutex and free memory of unit. */
250 destroy_unit_mutex (gfc_unit
*u
)
252 __gthread_mutex_destroy (&u
->lock
);
258 delete_root (gfc_unit
*t
)
264 if (t
->right
== NULL
)
267 if (t
->left
->priority
> t
->right
->priority
)
269 temp
= rotate_right (t
);
270 temp
->right
= delete_root (t
);
274 temp
= rotate_left (t
);
275 temp
->left
= delete_root (t
);
282 /* delete_treap()-- Delete an element from a tree. The 'old' value
283 does not necessarily have to point to the element to be deleted, it
284 must just point to a treap structure with the key to be deleted.
285 Returns the new root node of the tree. */
288 delete_treap (gfc_unit
*old
, gfc_unit
*t
)
295 c
= compare (old
->unit_number
, t
->unit_number
);
298 t
->left
= delete_treap (old
, t
->left
);
300 t
->right
= delete_treap (old
, t
->right
);
308 /* delete_unit()-- Delete a unit from a tree */
311 delete_unit (gfc_unit
*old
)
313 unit_root
= delete_treap (old
, unit_root
);
317 /* get_gfc_unit()-- Given an integer, return a pointer to the unit
318 structure. Returns NULL if the unit does not exist,
319 otherwise returns a locked unit. */
322 get_gfc_unit (int n
, int do_create
)
327 __gthread_mutex_lock (&unit_lock
);
329 for (c
= 0; c
< CACHE_SIZE
; c
++)
330 if (unit_cache
[c
] != NULL
&& unit_cache
[c
]->unit_number
== n
)
339 c
= compare (n
, p
->unit_number
);
348 if (p
== NULL
&& do_create
)
356 for (c
= 0; c
< CACHE_SIZE
- 1; c
++)
357 unit_cache
[c
] = unit_cache
[c
+ 1];
359 unit_cache
[CACHE_SIZE
- 1] = p
;
364 /* Newly created units have their lock held already
365 from insert_unit. Just unlock UNIT_LOCK and return. */
366 __gthread_mutex_unlock (&unit_lock
);
371 if (p
!= NULL
&& (p
->child_dtio
== 0))
374 if (! __gthread_mutex_trylock (&p
->lock
))
376 /* assert (p->closed == 0); */
377 __gthread_mutex_unlock (&unit_lock
);
381 inc_waiting_locked (p
);
385 __gthread_mutex_unlock (&unit_lock
);
387 if (p
!= NULL
&& (p
->child_dtio
== 0))
389 __gthread_mutex_lock (&p
->lock
);
392 __gthread_mutex_lock (&unit_lock
);
393 __gthread_mutex_unlock (&p
->lock
);
394 if (predec_waiting_locked (p
) == 0)
395 destroy_unit_mutex (p
);
399 dec_waiting_unlocked (p
);
408 return get_gfc_unit (n
, 0);
413 find_or_create_unit (int n
)
415 return get_gfc_unit (n
, 1);
419 /* Helper function to check rank, stride, format string, and namelist.
420 This is used for optimization. You can't trim out blanks or shorten
421 the string if trailing spaces are significant. */
423 is_trim_ok (st_parameter_dt
*dtp
)
425 /* Check rank and stride. */
426 if (dtp
->internal_unit_desc
)
428 /* Format strings can not have 'BZ' or '/'. */
429 if (dtp
->common
.flags
& IOPARM_DT_HAS_FORMAT
)
431 char *p
= dtp
->format
;
433 if (dtp
->common
.flags
& IOPARM_DT_HAS_BLANK
)
435 for (i
= 0; i
< dtp
->format_len
; i
++)
437 if (p
[i
] == '/') return false;
438 if (p
[i
] == 'b' || p
[i
] == 'B')
439 if (p
[i
+1] == 'z' || p
[i
+1] == 'Z')
443 if (dtp
->u
.p
.ionml
) /* A namelist. */
450 set_internal_unit (st_parameter_dt
*dtp
, gfc_unit
*iunit
, int kind
)
452 gfc_offset start_record
= 0;
454 iunit
->unit_number
= dtp
->common
.unit
;
455 iunit
->recl
= dtp
->internal_unit_len
;
456 iunit
->internal_unit
= dtp
->internal_unit
;
457 iunit
->internal_unit_len
= dtp
->internal_unit_len
;
458 iunit
->internal_unit_kind
= kind
;
460 /* As an optimization, adjust the unit record length to not
461 include trailing blanks. This will not work under certain conditions
462 where trailing blanks have significance. */
463 if (dtp
->u
.p
.mode
== READING
&& is_trim_ok (dtp
))
467 len
= string_len_trim (iunit
->internal_unit_len
,
468 iunit
->internal_unit
);
470 len
= string_len_trim_char4 (iunit
->internal_unit_len
,
471 (const gfc_char4_t
*) iunit
->internal_unit
);
472 iunit
->internal_unit_len
= len
;
473 iunit
->recl
= iunit
->internal_unit_len
;
476 /* Set up the looping specification from the array descriptor, if any. */
478 if (is_array_io (dtp
))
480 iunit
->rank
= GFC_DESCRIPTOR_RANK (dtp
->internal_unit_desc
);
481 iunit
->ls
= (array_loop_spec
*)
482 xmallocarray (iunit
->rank
, sizeof (array_loop_spec
));
483 iunit
->internal_unit_len
*=
484 init_loop_spec (dtp
->internal_unit_desc
, iunit
->ls
, &start_record
);
486 start_record
*= iunit
->recl
;
489 /* Set initial values for unit parameters. */
491 iunit
->s
= open_internal4 (iunit
->internal_unit
- start_record
,
492 iunit
->internal_unit_len
, -start_record
);
494 iunit
->s
= open_internal (iunit
->internal_unit
- start_record
,
495 iunit
->internal_unit_len
, -start_record
);
497 iunit
->bytes_left
= iunit
->recl
;
498 iunit
->last_record
=0;
500 iunit
->current_record
=0;
502 iunit
->endfile
= NO_ENDFILE
;
504 /* Set flags for the internal unit. */
506 iunit
->flags
.access
= ACCESS_SEQUENTIAL
;
507 iunit
->flags
.action
= ACTION_READWRITE
;
508 iunit
->flags
.blank
= BLANK_NULL
;
509 iunit
->flags
.form
= FORM_FORMATTED
;
510 iunit
->flags
.pad
= PAD_YES
;
511 iunit
->flags
.status
= STATUS_UNSPECIFIED
;
512 iunit
->flags
.sign
= SIGN_UNSPECIFIED
;
513 iunit
->flags
.decimal
= DECIMAL_POINT
;
514 iunit
->flags
.delim
= DELIM_UNSPECIFIED
;
515 iunit
->flags
.encoding
= ENCODING_DEFAULT
;
516 iunit
->flags
.async
= ASYNC_NO
;
517 iunit
->flags
.round
= ROUND_UNSPECIFIED
;
519 /* Initialize the data transfer parameters. */
521 dtp
->u
.p
.advance_status
= ADVANCE_YES
;
522 dtp
->u
.p
.seen_dollar
= 0;
524 dtp
->u
.p
.pending_spaces
= 0;
525 dtp
->u
.p
.max_pos
= 0;
531 /* get_unit()-- Returns the unit structure associated with the integer
532 unit or the internal file. */
535 get_unit (st_parameter_dt
*dtp
, int do_create
)
539 if ((dtp
->common
.flags
& IOPARM_DT_HAS_INTERNAL_UNIT
) != 0)
542 if (dtp
->common
.unit
== GFC_INTERNAL_UNIT
)
544 else if (dtp
->common
.unit
== GFC_INTERNAL_UNIT4
)
547 internal_error (&dtp
->common
, "get_unit(): Bad internal unit KIND");
549 dtp
->u
.p
.unit_is_internal
= 1;
550 dtp
->common
.unit
= newunit_alloc ();
551 unit
= get_gfc_unit (dtp
->common
.unit
, do_create
);
552 set_internal_unit (dtp
, unit
, kind
);
553 fbuf_init (unit
, 128);
557 /* Has to be an external unit. */
558 dtp
->u
.p
.unit_is_internal
= 0;
559 dtp
->internal_unit
= NULL
;
560 dtp
->internal_unit_desc
= NULL
;
562 /* For an external unit with unit number < 0 creating it on the fly
563 is not allowed, such units must be created with
564 OPEN(NEWUNIT=...). */
565 if (dtp
->common
.unit
< 0)
566 return get_gfc_unit (dtp
->common
.unit
, 0);
568 return get_gfc_unit (dtp
->common
.unit
, do_create
);
572 /*************************/
573 /* Initialize everything. */
581 #ifdef HAVE_NEWLOCALE
582 c_locale
= newlocale (0, "C", 0);
584 #ifndef __GTHREAD_MUTEX_INIT
585 __GTHREAD_MUTEX_INIT_FUNCTION (&old_locale_lock
);
589 #ifndef __GTHREAD_MUTEX_INIT
590 __GTHREAD_MUTEX_INIT_FUNCTION (&unit_lock
);
593 if (options
.stdin_unit
>= 0)
595 u
= insert_unit (options
.stdin_unit
);
596 u
->s
= input_stream ();
598 u
->flags
.action
= ACTION_READ
;
600 u
->flags
.access
= ACCESS_SEQUENTIAL
;
601 u
->flags
.form
= FORM_FORMATTED
;
602 u
->flags
.status
= STATUS_OLD
;
603 u
->flags
.blank
= BLANK_NULL
;
604 u
->flags
.pad
= PAD_YES
;
605 u
->flags
.position
= POSITION_ASIS
;
606 u
->flags
.sign
= SIGN_UNSPECIFIED
;
607 u
->flags
.decimal
= DECIMAL_POINT
;
608 u
->flags
.delim
= DELIM_UNSPECIFIED
;
609 u
->flags
.encoding
= ENCODING_DEFAULT
;
610 u
->flags
.async
= ASYNC_NO
;
611 u
->flags
.round
= ROUND_UNSPECIFIED
;
612 u
->flags
.share
= SHARE_UNSPECIFIED
;
613 u
->flags
.cc
= CC_LIST
;
615 u
->recl
= options
.default_recl
;
616 u
->endfile
= NO_ENDFILE
;
618 u
->filename
= strdup (stdin_name
);
622 __gthread_mutex_unlock (&u
->lock
);
625 if (options
.stdout_unit
>= 0)
627 u
= insert_unit (options
.stdout_unit
);
628 u
->s
= output_stream ();
630 u
->flags
.action
= ACTION_WRITE
;
632 u
->flags
.access
= ACCESS_SEQUENTIAL
;
633 u
->flags
.form
= FORM_FORMATTED
;
634 u
->flags
.status
= STATUS_OLD
;
635 u
->flags
.blank
= BLANK_NULL
;
636 u
->flags
.position
= POSITION_ASIS
;
637 u
->flags
.sign
= SIGN_UNSPECIFIED
;
638 u
->flags
.decimal
= DECIMAL_POINT
;
639 u
->flags
.delim
= DELIM_UNSPECIFIED
;
640 u
->flags
.encoding
= ENCODING_DEFAULT
;
641 u
->flags
.async
= ASYNC_NO
;
642 u
->flags
.round
= ROUND_UNSPECIFIED
;
643 u
->flags
.share
= SHARE_UNSPECIFIED
;
644 u
->flags
.cc
= CC_LIST
;
646 u
->recl
= options
.default_recl
;
647 u
->endfile
= AT_ENDFILE
;
649 u
->filename
= strdup (stdout_name
);
653 __gthread_mutex_unlock (&u
->lock
);
656 if (options
.stderr_unit
>= 0)
658 u
= insert_unit (options
.stderr_unit
);
659 u
->s
= error_stream ();
661 u
->flags
.action
= ACTION_WRITE
;
663 u
->flags
.access
= ACCESS_SEQUENTIAL
;
664 u
->flags
.form
= FORM_FORMATTED
;
665 u
->flags
.status
= STATUS_OLD
;
666 u
->flags
.blank
= BLANK_NULL
;
667 u
->flags
.position
= POSITION_ASIS
;
668 u
->flags
.sign
= SIGN_UNSPECIFIED
;
669 u
->flags
.decimal
= DECIMAL_POINT
;
670 u
->flags
.encoding
= ENCODING_DEFAULT
;
671 u
->flags
.async
= ASYNC_NO
;
672 u
->flags
.round
= ROUND_UNSPECIFIED
;
673 u
->flags
.share
= SHARE_UNSPECIFIED
;
674 u
->flags
.cc
= CC_LIST
;
676 u
->recl
= options
.default_recl
;
677 u
->endfile
= AT_ENDFILE
;
679 u
->filename
= strdup (stderr_name
);
681 fbuf_init (u
, 256); /* 256 bytes should be enough, probably not doing
682 any kind of exotic formatting to stderr. */
684 __gthread_mutex_unlock (&u
->lock
);
687 /* Calculate the maximum file offset in a portable manner.
688 max will be the largest signed number for the type gfc_offset.
689 set a 1 in the LSB and keep a running sum, stopping at MSB-1 bit. */
691 for (i
= 0; i
< sizeof (max_offset
) * 8 - 1; i
++)
692 max_offset
= max_offset
+ ((gfc_offset
) 1 << i
);
697 close_unit_1 (gfc_unit
*u
, int locked
)
701 /* If there are previously written bytes from a write with ADVANCE="no"
702 Reposition the buffer before closing. */
703 if (u
->previous_nonadvancing_write
)
704 finish_last_advance_record (u
);
706 rc
= (u
->s
== NULL
) ? 0 : sclose (u
->s
) == -1;
710 __gthread_mutex_lock (&unit_lock
);
712 for (i
= 0; i
< CACHE_SIZE
; i
++)
713 if (unit_cache
[i
] == u
)
714 unit_cache
[i
] = NULL
;
721 free_format_hash_table (u
);
724 if (u
->unit_number
<= NEWUNIT_START
)
725 newunit_free (u
->unit_number
);
728 __gthread_mutex_unlock (&u
->lock
);
730 /* If there are any threads waiting in find_unit for this unit,
731 avoid freeing the memory, the last such thread will free it
734 destroy_unit_mutex (u
);
737 __gthread_mutex_unlock (&unit_lock
);
743 unlock_unit (gfc_unit
*u
)
745 __gthread_mutex_unlock (&u
->lock
);
748 /* close_unit()-- Close a unit. The stream is closed, and any memory
749 associated with the stream is freed. Returns nonzero on I/O error.
750 Should be called with the u->lock locked. */
753 close_unit (gfc_unit
*u
)
755 return close_unit_1 (u
, 0);
759 /* close_units()-- Delete units on completion. We just keep deleting
760 the root of the treap until there is nothing left.
761 Not sure what to do with locking here. Some other thread might be
762 holding some unit's lock and perhaps hold it indefinitely
763 (e.g. waiting for input from some pipe) and close_units shouldn't
764 delay the program too much. */
769 __gthread_mutex_lock (&unit_lock
);
770 while (unit_root
!= NULL
)
771 close_unit_1 (unit_root
, 1);
772 __gthread_mutex_unlock (&unit_lock
);
776 #ifdef HAVE_FREELOCALE
777 freelocale (c_locale
);
782 /* High level interface to truncate a file, i.e. flush format buffers,
783 and generate an error or set some flags. Just like POSIX
784 ftruncate, returns 0 on success, -1 on failure. */
787 unit_truncate (gfc_unit
*u
, gfc_offset pos
, st_parameter_common
*common
)
791 /* Make sure format buffer is flushed. */
792 if (u
->flags
.form
== FORM_FORMATTED
)
794 if (u
->mode
== READING
)
795 pos
+= fbuf_reset (u
);
797 fbuf_flush (u
, u
->mode
);
800 /* struncate() should flush the stream buffer if necessary, so don't
801 bother calling sflush() here. */
802 ret
= struncate (u
->s
, pos
);
805 generate_error (common
, LIBERROR_OS
, NULL
);
808 u
->endfile
= AT_ENDFILE
;
809 u
->flags
.position
= POSITION_APPEND
;
816 /* filename_from_unit()-- If the unit_number exists, return a pointer to the
817 name of the associated file, otherwise return the empty string. The caller
818 must free memory allocated for the filename string. */
821 filename_from_unit (int n
)
830 c
= compare (n
, u
->unit_number
);
839 /* Get the filename. */
840 if (u
!= NULL
&& u
->filename
!= NULL
)
841 return strdup (u
->filename
);
843 return (char *) NULL
;
847 finish_last_advance_record (gfc_unit
*u
)
850 if (u
->saved_pos
> 0)
851 fbuf_seek (u
, u
->saved_pos
, SEEK_CUR
);
853 if (!(u
->unit_number
== options
.stdout_unit
854 || u
->unit_number
== options
.stderr_unit
))
861 char *p
= fbuf_alloc (u
, len
);
863 os_error ("Completing record after ADVANCE_NO failed");
870 fbuf_flush (u
, u
->mode
);
874 /* Assign a negative number for NEWUNIT in OPEN statements or for
879 __gthread_mutex_lock (&unit_lock
);
882 newunits
= xcalloc (16, 1);
886 /* Search for the next available newunit. */
887 for (int ii
= newunit_lwi
; ii
< newunit_size
; ii
++)
892 newunit_lwi
= ii
+ 1;
893 __gthread_mutex_unlock (&unit_lock
);
894 return -ii
+ NEWUNIT_START
;
898 /* Search failed, bump size of array and allocate the first
900 int old_size
= newunit_size
;
902 newunits
= xrealloc (newunits
, newunit_size
);
903 memset (newunits
+ old_size
, 0, old_size
);
904 newunits
[old_size
] = true;
905 newunit_lwi
= old_size
+ 1;
906 __gthread_mutex_unlock (&unit_lock
);
907 return -old_size
+ NEWUNIT_START
;
911 /* Free a previously allocated newunit= unit number. unit_lock must
912 be held when calling. */
915 newunit_free (int unit
)
917 int ind
= -unit
+ NEWUNIT_START
;
918 assert(ind
>= 0 && ind
< newunit_size
);
919 newunits
[ind
] = false;
920 if (ind
< newunit_lwi
)