diff --git a/src/flag.rs b/src/flag.rs
index 3eb11ad..d831f1f 100644
--- a/src/flag.rs
+++ b/src/flag.rs
@@ -293,6 +293,7 @@ bitflags! {
 
 // Auxiliery vector types
 pub const AT_NULL: usize = 0;
+pub const AT_PHDR: usize = 3;
 pub const AT_ENTRY: usize = 9;
 
 bitflags! {