diff --git a/headers/posix/libio.h b/headers/posix/libio.h
index b8711c4afe..15d2cf18e8 100644
--- a/headers/posix/libio.h
+++ b/headers/posix/libio.h
@@ -31,7 +31,7 @@
 #include <stdarg.h>
 
 #ifndef EOF
-#	define EOF -1
+#	define EOF (-1)
 #endif
 
 #define _IO_pos_t		off_t /* obsolete */
diff --git a/headers/posix/stdio.h b/headers/posix/stdio.h
index b40328ea08..d3e01c4821 100644
--- a/headers/posix/stdio.h
+++ b/headers/posix/stdio.h
@@ -39,7 +39,7 @@
 #ifdef EOF
 #	undef EOF
 #endif
-#define EOF -1
+#define EOF (-1)
 
 #ifndef SEEK_SET
 #	define SEEK_SET 0