Index: src/btree.c
==================================================================
--- src/btree.c
+++ src/btree.c
@@ -1692,11 +1692,11 @@
   /*
   ** If this Btree is a candidate for shared cache, try to find an
   ** existing BtShared object that we can share with
   */
   if( isMemdb==0 && zFilename && zFilename[0] ){
-    if( sqlite3GlobalConfig.sharedCacheEnabled ){
+    if( vfsFlags & SQLITE_OPEN_SHAREDCACHE ){
       int nFullPathname = pVfs->mxPathname+1;
       char *zFullPathname = sqlite3Malloc(nFullPathname);
       sqlite3_mutex *mutexShared;
       p->sharable = 1;
       if( !zFullPathname ){

Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -1541,10 +1541,15 @@
     isThreadsafe = 0;
   }else if( flags & SQLITE_OPEN_FULLMUTEX ){
     isThreadsafe = 1;
   }else{
     isThreadsafe = sqlite3GlobalConfig.bFullMutex;
+  }
+  if( flags & SQLITE_OPEN_PRIVATECACHE ){
+    flags &= SQLITE_OPEN_SHAREDCACHE;
+  }else if( sqlite3GlobalConfig.sharedCacheEnabled ){
+    flags |= SQLITE_OPEN_SHAREDCACHE;
   }
 
   /* Remove harmful bits from the flags parameter
   **
   ** The SQLITE_OPEN_NOMUTEX and SQLITE_OPEN_FULLMUTEX flags were

Index: src/os.c
==================================================================
--- src/os.c
+++ src/os.c
@@ -112,11 +112,15 @@
   int flags, 
   int *pFlagsOut
 ){
   int rc;
   DO_OS_MALLOC_TEST(0);
-  rc = pVfs->xOpen(pVfs, zPath, pFile, flags, pFlagsOut);
+  /* 0x7f1f is a mask of SQLITE_OPEN_ flags that are valid to be passed
+  ** down into the VFS layer.  Some SQLITE_OPEN_ flags (for example,
+  ** SQLITE_OPEN_FULLMUTEX or SQLITE_OPEN_SHAREDCACHE) are blocked before
+  ** reaching the VFS. */
+  rc = pVfs->xOpen(pVfs, zPath, pFile, flags & 0x7f1f, pFlagsOut);
   assert( rc==SQLITE_OK || pFile->pMethods==0 );
   return rc;
 }
 int sqlite3OsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
   return pVfs->xDelete(pVfs, zPath, dirSync);

Index: src/sqlite.h.in
==================================================================
--- src/sqlite.h.in
+++ src/sqlite.h.in
@@ -432,10 +432,12 @@
 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
+#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
 
 /*
 ** CAPI3REF: Device Characteristics {H10240} <H11120>
 **
 ** The xDeviceCapabilities method of the [sqlite3_io_methods]
@@ -2093,11 +2095,12 @@
 **
 ** The sqlite3_open_v2() interface works like sqlite3_open()
 ** except that it accepts two additional parameters for additional control
 ** over the new database connection.  The flags parameter can take one of
 ** the following three values, optionally combined with the 
-** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags:
+** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
+** and/or [SQLITE_OPEN_PRIVATECACHE] flags:
 **
 ** <dl>
 ** <dt>[SQLITE_OPEN_READONLY]</dt>
 ** <dd>The database is opened in read-only mode.  If the database does not
 ** already exist, an error is returned.</dd>
@@ -2113,19 +2116,25 @@
 ** sqlite3_open() and sqlite3_open16().</dd>
 ** </dl>
 **
 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
 ** combinations shown above or one of the combinations shown above combined
-** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags,
+** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX],
+** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags,
 ** then the behavior is undefined.
 **
 ** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
 ** opens in the multi-thread [threading mode] as long as the single-thread
 ** mode has not been set at compile-time or start-time.  If the
 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
 ** in the serialized [threading mode] unless single-thread was
 ** previously selected at compile-time or start-time.
+** The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
+** eligible to use [shared cache mode], regardless of whether or not shared
+** cache is enabled using [sqlite3_enable_shared_cache()].  The
+** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
+** participate in [shared cache mode] even if it is enabled.
 **
 ** If the filename is ":memory:", then a private, temporary in-memory database
 ** is created for the connection.  This in-memory database will vanish when
 ** the database connection is closed.  Future versions of SQLite might
 ** make use of additional special filenames that begin with the ":" character.