diff --git a/include/runlist.h b/include/runlist.h
index 62ad9431..8a369fbd 100644
--- a/include/runlist.h
+++ b/include/runlist.h
@@ -63,5 +63,7 @@ extern runlist_element *ntfs_mapping_pairs_decompress(const ntfs_volume *vol,
 extern int ntfs_mapping_pairs_build(const ntfs_volume *vol, s8 *dst,
 		const int dst_len, const runlist_element *rl);
 
+extern int ntfs_rl_truncate(runlist_element *rl, const VCN start_vcn);
+
 #endif /* defined _NTFS_RUNLIST_H */
 
diff --git a/libntfs/runlist.c b/libntfs/runlist.c
index 0fbf2ced..3e3d70cc 100644
--- a/libntfs/runlist.c
+++ b/libntfs/runlist.c
@@ -1106,7 +1106,7 @@ rl_err_out:
  *
  * Create the mapping pairs array from the runlist @rl and save the array in
  * @dst. @dst_len is the size of @dst in bytes and it should be at least equal
- * to the value obtained by calling ntfs_get_size_for_mapping_pairs(@rl).
+ * to the value obtained by calling ntfs_get_size_for_mapping_pairs().
  *
  * Return 0 on success or when @rl is NULL. On error, return -1 with errno set
  * to the error code. The following error codes are defined:
@@ -1174,3 +1174,19 @@ err_out:
 	return -1;
 }
 
+/**
+ * ntfs_rl_truncate - truncate a runlist starting at a specified vcn
+ * @rl:		runlist to truncate
+ * @start_vcn:	first vcn which should be cut off
+ *
+ * Truncate the runlist @rl starting at vcn @start_vcn as well as the memory
+ * buffer holding the runlist.
+ *
+ * Return 0 on success and -1 on error with errno set to the error code.
+ */
+int ntfs_rl_truncate(runlist_element *rl, const VCN start_vcn)
+{
+	errno = ENOTSUP;
+	return -1;
+}
+