Switch the example project to use the new .options file

example/fileproto.options

+# This file defines the nanopb-specific options for the messages defined
+# in fileproto.proto.
+#
+# If you come from high-level programming background, the hardcoded
+# maximum lengths may disgust you. However, if your microcontroller only
+# has a few kB of ram to begin with, setting reasonable limits for
+# filenames is ok.
+#
+# On the other hand, using the callback interface, it is not necessary
+# to set a limit on the number of files in the response.
+
+ListFilesRequest.path 	max_size:128
+FileInfo.name 		max_size:128

example/fileproto.proto

-import "nanopb.proto";
-
 // This defines protocol for a simple server that lists files.
 //
-// If you come from high-level programming background, the hardcoded
-// maximum lengths may disgust you. However, if your microcontroller only
-// has a few kB of ram to begin with, setting reasonable limits for
-// filenames is ok.
-//
-// On the other hand, using the callback interface, it is not necessary
-// to set a limit on the number of files in the response.
+// See also the nanopb-specific options in fileproto.options.
 
 message ListFilesRequest {
-    optional string path = 1 [default = "/", (nanopb).max_size = 128];
+    optional string path = 1 [default = "/"];
 }
 
 message FileInfo {
     required uint64 inode = 1;
-    required string name = 2 [(nanopb).max_size = 128];
+    required string name = 2;
 }
 
 message ListFilesResponse {