diff --git a/sysfs.cpp b/sysfs.cpp
index b0c5a6d..af5f86a 100644
--- a/sysfs.cpp
+++ b/sysfs.cpp
@@ -267,6 +267,7 @@
     {
         try
         {
+            errno = 0;
             if (!ifs.is_open())
                 ifs.open(fullPath);
             ifs.clear();
@@ -343,6 +344,7 @@
     {
         try
         {
+            errno = 0;
             if (!ofs.is_open())
                 ofs.open(fullPath);
             ofs.clear();