diff --git a/src/internals/rules.rs b/src/internals/rules.rs
index 0d631f6..3823d3d 100644
--- a/src/internals/rules.rs
+++ b/src/internals/rules.rs
@@ -164,7 +164,7 @@ impl<'a> Iterator for RuleIterator<'a> {
         let rule = unsafe { *self.head };
         let mut result: Option<Self::Item> = None;
 
-        if (rule.flags & yara_sys::RULE_FLAGS_NULL) != 0 {
+        if ((rule.flags as u32) & yara_sys::RULE_FLAGS_NULL) != 0 {
             self.head = std::ptr::null();
         } else {
             let rule_data = Rule::from(unsafe { &*self.head });
diff --git a/yara-sys/build.rs b/yara-sys/build.rs
index 4f0898f..1b3029b 100644
--- a/yara-sys/build.rs
+++ b/yara-sys/build.rs
@@ -395,6 +395,7 @@ mod bindings {
             .allowlist_var("META_FLAGS_LAST_IN_RULE")
             .allowlist_var("OBJECT_TYPE_.*")
             .allowlist_var("STRING_FLAGS_LAST_IN_RULE")
+            .allowlist_var("RULE_FLAGS_NULL")
             .allowlist_var("YARA_ERROR_LEVEL_.*")
             .allowlist_var("SCAN_FLAGS_.*")
             .allowlist_var("YR_CONFIG_.*")
diff --git a/yara-sys/src/lib.rs b/yara-sys/src/lib.rs
index 39fc36d..eb25832 100644
--- a/yara-sys/src/lib.rs
+++ b/yara-sys/src/lib.rs
@@ -2,8 +2,6 @@
 #![allow(non_snake_case)]
 #![allow(non_upper_case_globals)]
 
-pub const RULE_FLAGS_NULL: i32 = 0x04;
-
 pub mod errors;
 
 pub use crate::errors::*;