diff --git a/resources/lib/std/io.c3 b/resources/lib/std/io.c3
index f69f66899..5651fad90 100644
--- a/resources/lib/std/io.c3
+++ b/resources/lib/std/io.c3
@@ -81,7 +81,7 @@ fn void! File.seek(File *file, long offset, Seek seekMode = Seek.SET)
 {
     if (libc::fseek(file.file, (SeekIndex)(offset), (int)(seekMode)))
     {
-        switch (libc::errno)
+        switch (libc::errno())
         {
             case EBADF: return IoError.FILE_NOT_SEEKABLE!;
             case EINVAL: return IoError.FILE_INVALID_POSITION!;
@@ -107,7 +107,7 @@ fn void! File.close(File *file) @inline
 {
     if (file.file && libc::fclose(file.file))
     {
-        switch (libc::errno)
+        switch (libc::errno())
         {
             case ECONNRESET:
             case EBADF: return IoError.FILE_NOT_VALID!;
diff --git a/resources/lib/std/libc.c3 b/resources/lib/std/libc.c3
index f3cc12ecd..ae521f226 100644
--- a/resources/lib/std/libc.c3
+++ b/resources/lib/std/libc.c3
@@ -160,7 +160,7 @@ enum Errno : ErrnoType
     ENOTRECOVERABLE = 131, /* State not recoverable */
 }
 
-extern Errno errno;
+extern fn Errno errno(void);
 
 define TerminateFunction = fn void();
 define CompareFunction = fn int(void*, void*);