Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -1061,10 +1061,11 @@
       case SQLITE_PERM:               zName = "SQLITE_PERM";              break;
       case SQLITE_ABORT:              zName = "SQLITE_ABORT";             break;
       case SQLITE_ABORT_ROLLBACK:     zName = "SQLITE_ABORT_ROLLBACK";    break;
       case SQLITE_BUSY:               zName = "SQLITE_BUSY";              break;
       case SQLITE_BUSY_RECOVERY:      zName = "SQLITE_BUSY_RECOVERY";     break;
+      case SQLITE_BUSY_SNAPSHOT:      zName = "SQLITE_BUSY_SNAPSHOT";     break;
       case SQLITE_LOCKED:             zName = "SQLITE_LOCKED";            break;
       case SQLITE_LOCKED_SHAREDCACHE: zName = "SQLITE_LOCKED_SHAREDCACHE";break;
       case SQLITE_NOMEM:              zName = "SQLITE_NOMEM";             break;
       case SQLITE_READONLY:           zName = "SQLITE_READONLY";          break;
       case SQLITE_READONLY_RECOVERY:  zName = "SQLITE_READONLY_RECOVERY"; break;

Index: src/sqlite.h.in
==================================================================
--- src/sqlite.h.in
+++ src/sqlite.h.in
@@ -473,10 +473,11 @@
 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
 #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
+#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
 #define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
 #define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))

Index: src/wal.c
==================================================================
--- src/wal.c
+++ src/wal.c
@@ -2461,11 +2461,11 @@
   ** the write is disallowed.
   */
   if( memcmp(&pWal->hdr, (void *)walIndexHdr(pWal), sizeof(WalIndexHdr))!=0 ){
     walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
     pWal->writeLock = 0;
-    rc = SQLITE_BUSY;
+    rc = SQLITE_BUSY_SNAPSHOT;
   }
 
   return rc;
 }
 

Index: test/wal6.test
==================================================================
--- test/wal6.test
+++ test/wal6.test
@@ -12,10 +12,11 @@
 # focus of this file is testing the operation of the library in
 # "PRAGMA journal_mode=WAL" mode.
 #
 
 set testdir [file dirname $argv0]
+set testprefix wal6
 source $testdir/tester.tcl
 source $testdir/lock_common.tcl
 source $testdir/wal_common.tcl
 source $testdir/malloc_common.tcl
 ifcapable !wal {finish_test ; return }
@@ -27,22 +28,22 @@
 forcedelete test.db
 
 set all_journal_modes {delete persist truncate memory off}
 foreach jmode $all_journal_modes {
 
-	do_test wal6-1.0.$jmode {
+  do_test wal6-1.0.$jmode {
     sqlite3 db test.db
     execsql "PRAGMA journal_mode = $jmode;"
-	} $jmode
-
-	do_test wal6-1.1.$jmode {
-	  execsql {
-	    CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
-	    INSERT INTO t1 VALUES(1,2);
-	    SELECT * FROM t1;
-	  }
-	} {1 2}
+  } $jmode
+
+  do_test wal6-1.1.$jmode {
+    execsql {
+      CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
+      INSERT INTO t1 VALUES(1,2);
+      SELECT * FROM t1;
+    }
+  } {1 2}
 
 # Under Windows, you'll get an error trying to delete
 # a file this is already opened.  Close the first connection
 # so the other tests work.
 if {$tcl_platform(platform)=="windows"} {
@@ -49,33 +50,98 @@
   if {$jmode=="persist" || $jmode=="truncate"} {
     db close
   }
 }
 
-	do_test wal6-1.2.$jmode {
-	  sqlite3 db2 test.db
-	  execsql {
-		PRAGMA journal_mode=WAL;
-		INSERT INTO t1 VALUES(3,4);
-		SELECT * FROM t1 ORDER BY a;
-	  } db2
-	} {wal 1 2 3 4}
+  do_test wal6-1.2.$jmode {
+    sqlite3 db2 test.db
+    execsql {
+    PRAGMA journal_mode=WAL;
+    INSERT INTO t1 VALUES(3,4);
+    SELECT * FROM t1 ORDER BY a;
+    } db2
+  } {wal 1 2 3 4}
 
 if {$tcl_platform(platform)=="windows"} {
   if {$jmode=="persist" || $jmode=="truncate"} {
-	  sqlite3 db test.db
+    sqlite3 db test.db
   }
 }
 
-	do_test wal6-1.3.$jmode {
-	  execsql {
-		  SELECT * FROM t1 ORDER BY a;
-	  }
-	} {1 2 3 4}
-
-	db close
-	db2 close
+  do_test wal6-1.3.$jmode {
+    execsql {
+      SELECT * FROM t1 ORDER BY a;
+    }
+  } {1 2 3 4}
+
+  db close
+  db2 close
   forcedelete test.db
 
 }
+
+#-------------------------------------------------------------------------
+# Test that SQLITE_BUSY_SNAPSHOT is returned as expected.
+#
+reset_db
+sqlite3 db2 test.db
+
+do_execsql_test 2.1 {
+  PRAGMA journal_mode = WAL;
+  CREATE TABLE t1(a PRIMARY KEY, b TEXT);
+  INSERT INTO t1 VALUES(1, 'one');
+  INSERT INTO t1 VALUES(2, 'two');
+  BEGIN;
+    SELECT * FROM t1;
+} {wal 1 one 2 two}
+
+do_test 2.2 {
+  execsql {
+    SELECT * FROM t1;
+    INSERT INTO t1 VALUES(3, 'three');
+  } db2
+} {1 one 2 two}
+
+do_catchsql_test 2.3 { 
+  INSERT INTO t1 VALUES('x', 'x') 
+} {1 {database is locked}}
+
+do_test 2.4 { 
+  list [sqlite3_errcode db] [sqlite3_extended_errcode db]
+} {SQLITE_BUSY SQLITE_BUSY_SNAPSHOT}
+
+do_execsql_test 2.5 {
+  SELECT * FROM t1;
+  COMMIT;
+  INSERT INTO t1 VALUES('x', 'x') 
+} {1 one 2 two}
+
+if 0 {
+proc test3 {prefix} {
+  do_test $prefix.1 {
+    execsql { SELECT count(*) FROM t1 } 
+  } {0}
+  do_test $prefix.2 {
+    execsql { INSERT INTO t1 VALUES('x', 'x') } db2
+  } {}
+  do_test $prefix.3 {
+    execsql { INSERT INTO t1 VALUES('y', 'y') }
+  } {}
+  do_test $prefix.4 {
+    execsql { SELECT count(*) FROM t1 } 
+  } {2}
+}
+
+do_execsql_test 2.6.1 { DELETE FROM t1 }
+test3 2.6.2
+
+db func test3 test3
+do_execsql_test 2.6.3 { DELETE FROM t1 }
+db eval {SELECT test3('2.6.4')}
+}
+
+do_test 2.x {
+  db2 close
+} {}
 
 finish_test
+