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Overview
Comment: | Improved documentation and addition of source-code evidence marks for the sqlite3_config() interface. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
681031a436fdd4cce426d6cd43cbae6b |
User & Date: | drh 2014-11-04 13:41:32.444 |
Context
2014-11-04
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14:22 | Change the definition of SQLITE_CONFIG_SCRATCH so that at most one scratch buffer is used per thread. Use the generic heap memory allocator for the WalIterator object when running a checkpoint. (check-in: 391c9b85ab user: drh tags: trunk) | |
13:41 | Improved documentation and addition of source-code evidence marks for the sqlite3_config() interface. (check-in: 681031a436 user: drh tags: trunk) | |
12:11 | Add the SQLITE_CONFIG_PCACHE_HDRSZ option for sqlite3_config(). (check-in: 6eb03e62a3 user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
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6645 6646 6647 6648 6649 6650 6651 | /* ** Allocate space for memory structures */ szScratch = nMaxCells*sizeof(u8*) /* apCell */ + nMaxCells*sizeof(u16) /* szCell */ + pBt->pageSize; /* aSpace1 */ | > > > > > | > | 6645 6646 6647 6648 6649 6650 6651 6652 6653 6654 6655 6656 6657 6658 6659 6660 6661 6662 6663 6664 6665 | /* ** Allocate space for memory structures */ szScratch = nMaxCells*sizeof(u8*) /* apCell */ + nMaxCells*sizeof(u16) /* szCell */ + pBt->pageSize; /* aSpace1 */ /* EVIDENCE-OF: R-37926-08392 SQLite will never request a scratch buffer ** that is more than 6 times the database page size, except when ** performing a checkpoint in WAL mode when the scratch buffer request ** size is a small fraction of the size of the WAL file. */ assert( szScratch<=6*pBt->pageSize ); apCell = sqlite3ScratchMalloc( szScratch ); if( apCell==0 ){ rc = SQLITE_NOMEM; goto balance_cleanup; } szCell = (u16*)&apCell[nMaxCells]; aSpace1 = (u8*)&szCell[nMaxCells]; |
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Changes to src/main.c.
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368 369 370 371 372 373 374 | /* Retrieve the current mutex implementation */ *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex; break; } #endif case SQLITE_CONFIG_MALLOC: { | > > > > | > > > | > > | | > > | > > > | > > | | > > > | > > > > > | > | 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 | /* Retrieve the current mutex implementation */ *va_arg(ap, sqlite3_mutex_methods*) = sqlite3GlobalConfig.mutex; break; } #endif case SQLITE_CONFIG_MALLOC: { /* EVIDENCE-OF: R-55594-21030 The SQLITE_CONFIG_MALLOC option takes a ** single argument which is a pointer to an instance of the ** sqlite3_mem_methods structure. The argument specifies alternative ** low-level memory allocation routines to be used in place of the memory ** allocation routines built into SQLite. */ sqlite3GlobalConfig.m = *va_arg(ap, sqlite3_mem_methods*); break; } case SQLITE_CONFIG_GETMALLOC: { /* EVIDENCE-OF: R-51213-46414 The SQLITE_CONFIG_GETMALLOC option takes a ** single argument which is a pointer to an instance of the ** sqlite3_mem_methods structure. The sqlite3_mem_methods structure is ** filled with the currently defined memory allocation routines. */ if( sqlite3GlobalConfig.m.xMalloc==0 ) sqlite3MemSetDefault(); *va_arg(ap, sqlite3_mem_methods*) = sqlite3GlobalConfig.m; break; } case SQLITE_CONFIG_MEMSTATUS: { /* EVIDENCE-OF: R-61275-35157 The SQLITE_CONFIG_MEMSTATUS option takes ** single argument of type int, interpreted as a boolean, which enables ** or disables the collection of memory allocation statistics. */ sqlite3GlobalConfig.bMemstat = va_arg(ap, int); break; } case SQLITE_CONFIG_SCRATCH: { /* EVIDENCE-OF: R-08404-60887 There are three arguments to ** SQLITE_CONFIG_SCRATCH: A pointer an 8-byte aligned memory buffer from ** which the scratch allocations will be drawn, the size of each scratch ** allocation (sz), and the maximum number of scratch allocations (N). */ sqlite3GlobalConfig.pScratch = va_arg(ap, void*); sqlite3GlobalConfig.szScratch = va_arg(ap, int); sqlite3GlobalConfig.nScratch = va_arg(ap, int); break; } case SQLITE_CONFIG_PAGECACHE: { /* EVIDENCE-OF: R-31408-40510 There are three arguments to ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory, the size ** of each page buffer (sz), and the number of pages (N). */ sqlite3GlobalConfig.pPage = va_arg(ap, void*); sqlite3GlobalConfig.szPage = va_arg(ap, int); sqlite3GlobalConfig.nPage = va_arg(ap, int); break; } case SQLITE_CONFIG_PCACHE_HDRSZ: { /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes ** a single parameter which is a pointer to an integer and writes into ** that integer the number of extra bytes per page required for each page ** in SQLITE_CONFIG_PAGECACHE. */ *va_arg(ap, int*) = sqlite3HeaderSizeBtree() + sqlite3HeaderSizePcache() + sqlite3HeaderSizePcache1(); break; } case SQLITE_CONFIG_PCACHE: { /* no-op */ break; } case SQLITE_CONFIG_GETPCACHE: { /* now an error */ rc = SQLITE_ERROR; break; } case SQLITE_CONFIG_PCACHE2: { /* EVIDENCE-OF: R-63325-48378 The SQLITE_CONFIG_PCACHE2 option takes a ** single argument which is a pointer to an sqlite3_pcache_methods2 ** object. This object specifies the interface to a custom page cache ** implementation. */ sqlite3GlobalConfig.pcache2 = *va_arg(ap, sqlite3_pcache_methods2*); break; } case SQLITE_CONFIG_GETPCACHE2: { /* EVIDENCE-OF: R-22035-46182 The SQLITE_CONFIG_GETPCACHE2 option takes a ** single argument which is a pointer to an sqlite3_pcache_methods2 ** object. SQLite copies of the current page cache implementation into ** that object. */ if( sqlite3GlobalConfig.pcache2.xInit==0 ){ sqlite3PCacheSetDefault(); } *va_arg(ap, sqlite3_pcache_methods2*) = sqlite3GlobalConfig.pcache2; break; } #if defined(SQLITE_ENABLE_MEMSYS3) || defined(SQLITE_ENABLE_MEMSYS5) case SQLITE_CONFIG_HEAP: { /* EVIDENCE-OF: R-19854-42126 There are three arguments to ** SQLITE_CONFIG_HEAP: An 8-byte aligned pointer to the memory, the ** number of bytes in the memory buffer, and the minimum allocation size. */ sqlite3GlobalConfig.pHeap = va_arg(ap, void*); sqlite3GlobalConfig.nHeap = va_arg(ap, int); sqlite3GlobalConfig.mnReq = va_arg(ap, int); if( sqlite3GlobalConfig.mnReq<1 ){ sqlite3GlobalConfig.mnReq = 1; }else if( sqlite3GlobalConfig.mnReq>(1<<12) ){ |
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Changes to src/sqlite.h.in.
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1495 1496 1497 1498 1499 1500 1501 | ** ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** it is not possible to set the Serialized [threading mode] and ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> ** ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> | | | > | | > | | | | | > | 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 | ** ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** it is not possible to set the Serialized [threading mode] and ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the ** SQLITE_CONFIG_SERIALIZED configuration option.</dd> ** ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is ** a pointer to an instance of the [sqlite3_mem_methods] structure. ** The argument specifies ** alternative low-level memory allocation routines to be used in place of ** the memory allocation routines built into SQLite.)^ ^SQLite makes ** its own private copy of the content of the [sqlite3_mem_methods] structure ** before the [sqlite3_config()] call returns.</dd> ** ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which ** is a pointer to an instance of the [sqlite3_mem_methods] structure. ** The [sqlite3_mem_methods] ** structure is filled with the currently defined memory allocation routines.)^ ** This option can be used to overload the default memory allocation ** routines with a wrapper that simulations memory allocation failure or ** tracks memory usage, for example. </dd> ** ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, ** interpreted as a boolean, which enables or disables the collection of ** memory allocation statistics. ^(When memory allocation statistics are disabled, the ** following SQLite interfaces become non-operational: ** <ul> ** <li> [sqlite3_memory_used()] ** <li> [sqlite3_memory_highwater()] ** <li> [sqlite3_soft_heap_limit64()] ** <li> [sqlite3_status()] ** </ul>)^ ** ^Memory allocation statistics are enabled by default unless SQLite is ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory ** allocation statistics are disabled by default. ** </dd> ** ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> ** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer ** that SQLite can use for scratch memory. ^(There are three arguments ** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte ** aligned memory buffer from which the scratch allocations will be ** drawn, the size of each scratch allocation (sz), ** and the maximum number of scratch allocations (N).)^ ** The first argument must be a pointer to an 8-byte aligned buffer ** of at least sz*N bytes of memory. ** ^SQLite will not use more than two scratch buffers per thread and not ** more than one scratch buffer per thread when not performing |
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1552 1553 1554 1555 1556 1557 1558 | ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large ** [sqlite3_malloc|heap allocations]. ** This can help [Robson proof|prevent memory allocation failures] due to heap ** fragmentation in low-memory embedded systems. ** </dd> ** ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> | | | > | | | | > | | | | | | | | | | | | | | | | | | | 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 | ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large ** [sqlite3_malloc|heap allocations]. ** This can help [Robson proof|prevent memory allocation failures] due to heap ** fragmentation in low-memory embedded systems. ** </dd> ** ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a static memory buffer ** that SQLite can use for the database page cache with the default page ** cache implementation. ** This configuration should not be used if an application-define page ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2] ** configuration option. ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned ** memory, the size of each page buffer (sz), and the number of pages (N). ** The sz argument should be the size of the largest database page ** (a power of two between 512 and 32768) plus some extra bytes for each ** page header. ^The number of extra bytes needed by the page header ** can be determined using the [SQLITE_CONFIG_PCACHE_HDRSZ] option ** to [sqlite3_config()]. ** ^It is harmless, apart from the wasted memory, ** for the sz parameter to be larger than necessary. The first ** argument should pointer to an 8-byte aligned block of memory that ** is at least sz*N bytes of memory, otherwise subsequent behavior is ** undefined. ** ^SQLite will use the memory provided by the first argument to satisfy its ** memory needs for the first N pages that it adds to cache. ^If additional ** page cache memory is needed beyond what is provided by this option, then ** SQLite goes to [sqlite3_malloc()] for the additional storage space.</dd> ** ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer ** that SQLite will use for all of its dynamic memory allocation needs ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. ** ^There are three arguments to SQLITE_CONFIG_HEAP: ** An 8-byte aligned pointer to the memory, ** the number of bytes in the memory buffer, and the minimum allocation size. ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts ** to using its default memory allocator (the system malloc() implementation), ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory ** allocator is engaged to handle all of SQLites memory allocation needs. ** The first pointer (the memory pointer) must be aligned to an 8-byte ** boundary or subsequent behavior of SQLite will be undefined. ** The minimum allocation size is capped at 2**12. Reasonable values ** for the minimum allocation size are 2**5 through 2**8.</dd> ** ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a ** pointer to an instance of the [sqlite3_mutex_methods] structure. ** The argument specifies alternative low-level mutex routines to be used in place ** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the ** content of the [sqlite3_mutex_methods] structure before the call to ** [sqlite3_config()] returns. ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** the entire mutexing subsystem is omitted from the build and hence calls to ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will ** return [SQLITE_ERROR].</dd> ** ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which ** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The ** [sqlite3_mutex_methods] ** structure is filled with the currently defined mutex routines.)^ ** This option can be used to overload the default mutex allocation ** routines with a wrapper used to track mutex usage for performance ** profiling or testing, for example. ^If SQLite is compiled with ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then ** the entire mutexing subsystem is omitted from the build and hence calls to ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will ** return [SQLITE_ERROR].</dd> ** ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine ** the default size of lookaside memory on each [database connection]. ** The first argument is the ** size of each lookaside buffer slot and the second is the number of ** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] ** option to [sqlite3_db_config()] can be used to change the lookaside ** configuration on individual connections.)^ </dd> ** ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is ** a pointer to an [sqlite3_pcache_methods2] object. This object specifies ** the interface to a custom page cache implementation.)^ ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> ** ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which ** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of the current ** page cache implementation into that object.)^ </dd> ** ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite ** global [error log]. ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a ** function with a call signature of void(*)(void*,int,const char*), |
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1658 1659 1660 1661 1662 1663 1664 | ** log message after formatting via [sqlite3_snprintf()]. ** The SQLite logging interface is not reentrant; the logger function ** supplied by the application must not invoke any SQLite interface. ** In a multi-threaded application, the application-defined logger ** function must be threadsafe. </dd> ** ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI | | | | | | | > | | 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 | ** log message after formatting via [sqlite3_snprintf()]. ** The SQLite logging interface is not reentrant; the logger function ** supplied by the application must not invoke any SQLite interface. ** In a multi-threaded application, the application-defined logger ** function must be threadsafe. </dd> ** ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. ** If non-zero, then URI handling is globally enabled. If the parameter is zero, ** then URI handling is globally disabled.)^ ^If URI handling is globally enabled, ** all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or ** specified as part of [ATTACH] commands are interpreted as URIs, regardless ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database ** connection is opened. ^If it is globally disabled, filenames are ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the ** database connection is opened. ^(By default, URI handling is globally ** disabled. The default value may be changed by compiling with the ** [SQLITE_USE_URI] symbol defined.)^ ** ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer ** argument which is interpreted as a boolean in order to enable or disable ** the use of covering indices for full table scans in the query optimizer. ** ^The default setting is determined ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" ** if that compile-time option is omitted. ** The ability to disable the use of covering indices for full table scans ** is because some incorrectly coded legacy applications might malfunction ** when the optimization is enabled. Providing the ability to ** disable the optimization allows the older, buggy application code to work ** without change even with newer versions of SQLite. |
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1721 1722 1723 1724 1725 1726 1727 | ** exceed the compile-time maximum mmap size set by the ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ ** ^If either argument to this option is negative, then that argument is ** changed to its compile-time default. ** ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE | | | | | | | | 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 | ** exceed the compile-time maximum mmap size set by the ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ ** ^If either argument to this option is negative, then that argument is ** changed to its compile-time default. ** ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro defined. ** ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value ** that specifies the maximum size of the created heap. ** </dl> ** ** [[SQLITE_CONFIG_PCACHE_HDRSZ]] ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which ** is a pointer to an integer and writes into that integer the number of extra ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. The amount of ** extra space required can change depending on the compiler, ** target platform, and SQLite version. ** </dl> */ #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ |
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