SQLite

#define TRANS_NONE  0
#define TRANS_READ  1
#define TRANS_WRITE 2

/*
** An instance of this object represents a single database file.
** 
** A single database file can be in use at the same time by two
** or more database connections.  When two or more connections are
** sharing the same database file, each connection has it own
** private Btree object for the file and each of those Btrees points
** to this one BtShared object.  BtShared.nRef is the number of
** connections currently sharing this database file.
**
** Fields in this structure are accessed under the BtShared.mutex

/*
** A cursor is a pointer to a particular entry within a particular
** b-tree within a database file.
**
** The entry is identified by its MemPage and the index in
** MemPage.aCell[] of the entry.
**
** A single database file can be shared by two more database connections,
** but cursors cannot be shared.  Each cursor is associated with a
** particular database connection identified BtCursor.pBtree.db.
**
** Fields in this structure are accessed under the BtShared.mutex
** found at self->pBt->mutex. 
*/
struct BtCursor {

  int mxErr;        /* Stop accumulating errors when this reaches zero */
  int nErr;         /* Number of messages written to zErrMsg so far */
  int mallocFailed; /* A memory allocation error has occurred */
  StrAccum errMsg;  /* Accumulate the error message text here */
};

/*
** Routines to read or write a two- and four-byte big-endian integer values.
*/
#define get2byte(x)   ((x)[0]<<8 | (x)[1])
#define put2byte(p,v) ((p)[0] = (u8)((v)>>8), (p)[1] = (u8)(v))
#define get4byte sqlite3Get4byte
#define put4byte sqlite3Put4byte

/* IMPLEMENTATION-OF: R-35210-63508 The sqlite3_libversion_number() function
** returns an integer equal to SQLITE_VERSION_NUMBER.
*/
int sqlite3_libversion_number(void){ return SQLITE_VERSION_NUMBER; }

/* IMPLEMENTATION-OF: R-54823-41343 The sqlite3_threadsafe() function returns
** zero if and only if SQLite was compiled with mutexing code omitted due to
** the SQLITE_THREADSAFE compile-time option being set to 0.
*/
int sqlite3_threadsafe(void){ return SQLITE_THREADSAFE; }

#if !defined(SQLITE_OMIT_TRACE) && defined(SQLITE_ENABLE_IOTRACE)
/*
** If the following function pointer is not NULL and if

const char *sqlite3_compileoption_get(int N);
#endif

/*
** CAPI3REF: Test To See If The Library Is Threadsafe
**
** ^The sqlite3_threadsafe() function returns zero if and only if
** SQLite was compiled with mutexing code omitted due to the
** [SQLITE_THREADSAFE] compile-time option being set to 0.
**
** SQLite can be compiled with or without mutexes.  When
** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
** are enabled and SQLite is threadsafe.  When the
** [SQLITE_THREADSAFE] macro is 0, 
** the mutexes are omitted.  Without the mutexes, it is not safe

  }

  /* Invalidate all ephemeral cursor row caches */
  p->cacheCtr = (p->cacheCtr + 2)|1;

  /* Make sure the results of the current row are \000 terminated
  ** and have an assigned type.  The results are de-ephemeralized as
  ** a side effect.
  */
  pMem = p->pResultSet = &aMem[pOp->p1];
  for(i=0; i<pOp->p2; i++){
    assert( memIsValid(&pMem[i]) );
    Deephemeralize(&pMem[i]);
    assert( (pMem[i].flags & MEM_Ephem)==0
            || (pMem[i].flags & (MEM_Str|MEM_Blob))==0 );

    ** be called automatically instead of throwing the SQLITE_MISUSE error.
    ** This "automatic-reset" change is not technically an incompatibility, 
    ** since any application that receives an SQLITE_MISUSE is broken by
    ** definition.
    **
    ** Nevertheless, some published applications that were originally written
    ** for version 3.6.23 or earlier do in fact depend on SQLITE_MISUSE 
    ** returns, and those were broken by the automatic-reset change.  As a
    ** a work-around, the SQLITE_OMIT_AUTORESET compile-time restores the
    ** legacy behavior of returning SQLITE_MISUSE for cases where the 
    ** previous sqlite3_step() returned something other than a SQLITE_LOCKED
    ** or SQLITE_BUSY error.
    */
#ifdef SQLITE_OMIT_AUTORESET
    if( p->rc==SQLITE_BUSY || p->rc==SQLITE_LOCKED ){

  if( pVm && pVm->pResultSet!=0 && i<pVm->nResColumn && i>=0 ){
    sqlite3_mutex_enter(pVm->db->mutex);
    pOut = &pVm->pResultSet[i];
  }else{
    /* If the value passed as the second argument is out of range, return
    ** a pointer to the following static Mem object which contains the
    ** value SQL NULL. Even though the Mem structure contains an element
    ** of type i64, on certain architectures (x86) with certain compiler
    ** switches (-Os), gcc may align this Mem object on a 4-byte boundary
    ** instead of an 8-byte one. This all works fine, except that when
    ** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
    ** that a Mem structure is located on an 8-byte boundary. To prevent
    ** these assert()s from failing, when building with SQLITE_DEBUG defined
    ** using gcc, we force nullMem to be 8-byte aligned using the magical
    ** __attribute__((aligned(8))) macro.  */
    static const Mem nullMem 
#if defined(SQLITE_DEBUG) && defined(__GNUC__)
      __attribute__((aligned(8))) 
#endif
      = {0, "", (double)0, {0}, 0, MEM_Null, SQLITE_NULL, 0,
#ifdef SQLITE_DEBUG