diff --git a/adb_utils.h b/adb_utils.h
index 739efcc..b38ec59 100644
--- a/adb_utils.h
+++ b/adb_utils.h
@@ -44,4 +44,6 @@
                          std::string* host, int* port,
                          std::string* error);
 
+std::string perror_str(const char* msg);
+
 #endif