diff --git a/generator/pio_lib_gen.py b/generator/pio_lib_gen.py
index 30d6510..d57c378 100644
--- a/generator/pio_lib_gen.py
+++ b/generator/pio_lib_gen.py
@@ -20,5 +20,14 @@
 build_dir = env.subst("$BUILD_DIR")
 
 generated_src_dir = os.path.join(build_dir, 'dbcppp', 'generated-src')
+generated_build_dir = os.path.join(build_dir, 'dbcppp', 'generated-build')
+
+user_dbc_files =  env.subst(env.GetProjectOption("user_dbcs", ""))
+
+dbc_files = fs.match_src_files(project_dir, user_dbc_files)
+if not len(protos_files):
+    print("[nanopb] ERROR: No files matched pattern:")
+    print(f"user_dbcs: {user_dbc_files}")
+    exit(1)
 
 print("hello from lib")
\ No newline at end of file