1 files changed, 5 insertions, 1 deletions
diff --git a/error.go b/error.go
index 7e879a1..7f867b2 100644
--- a/error.go
+++ b/error.go
@@ -4,7 +4,7 @@ var (
 	// ErrInvalid is returned when a data file is not a Bolt-formatted database.
 	ErrInvalid = &Error{"Invalid database", nil}
 
-	// ErrVersionMismatch is returned when the data file was created with a 
+	// ErrVersionMismatch is returned when the data file was created with a
 	// different version of Bolt.
 	ErrVersionMismatch = &Error{"version mismatch", nil}
 
@@ -16,6 +16,10 @@ var (
 	// already open.
 	ErrDatabaseOpen = &Error{"database already open", nil}
 
+	// ErrTxNotWritable is returned when performing a write operation on a
+	// read-only transaction.
+	ErrTxNotWritable = &Error{"tx not writable", nil}
+
 	// ErrBucketNotFound is returned when trying to access a bucket that has
 	// not been created yet.
 	ErrBucketNotFound = &Error{"bucket not found", nil}