4 files changed, 35 insertions, 2 deletions
diff --git a/bindgen-integration/build.rs b/bindgen-integration/build.rs
index 1a86add1..cadec267 100644
--- a/bindgen-integration/build.rs
+++ b/bindgen-integration/build.rs
@@ -4,13 +4,14 @@ extern crate gcc;
 use std::collections::HashSet;
 use std::env;
 use std::path::PathBuf;
-use std::sync::{Arc, RwLock};
+use std::sync::{Arc, RwLock, Mutex};
 use bindgen::Builder;
 use bindgen::callbacks::{MacroParsingBehavior, ParseCallbacks};
 
 #[derive(Debug)]
 struct MacroCallback {
     macros: Arc<RwLock<HashSet<String>>>,
+    seen_hellos: Mutex<u32>,
 }
 
 impl ParseCallbacks for MacroCallback {
@@ -33,6 +34,26 @@ impl ParseCallbacks for MacroCallback {
             None
         }
     }
+
+    fn str_macro(&self, name: &str, value: &[u8]) {
+        match &name {
+            &"TESTMACRO_STRING_EXPANDED" |
+            &"TESTMACRO_STRING" |
+            &"TESTMACRO_INTEGER" => {
+                // The integer test macro is, actually, not expected to show up here at all -- but
+                // should produce an error if it does.
+                assert_eq!(value, b"Hello Preprocessor!", "str_macro handle received unexpected value");
+                *self.seen_hellos.lock().unwrap() += 1;
+            },
+            _ => {}
+        }
+    }
+}
+
+impl Drop for MacroCallback {
+    fn drop(&mut self) {
+        assert_eq!(*self.seen_hellos.lock().unwrap(), 2, "str_macro handle was not called once for all relevant macros")
+    }
 }
 
 fn main() {
@@ -51,7 +72,7 @@ fn main() {
         .module_raw_line("root::testing", "pub type Bar = i32;")
         .header("cpp/Test.h")
         .clang_args(&["-x", "c++", "-std=c++11"])
-        .parse_callbacks(Box::new(MacroCallback {macros: macros.clone()}))
+        .parse_callbacks(Box::new(MacroCallback {macros: macros.clone(), seen_hellos: Mutex::new(0)}))
         .generate()
         .expect("Unable to generate bindings");
 
diff --git a/bindgen-integration/cpp/Test.h b/bindgen-integration/cpp/Test.h
index fe9bf0d4..03a55b88 100644
--- a/bindgen-integration/cpp/Test.h
+++ b/bindgen-integration/cpp/Test.h
@@ -2,6 +2,10 @@
 
 #define TESTMACRO
 
+#define TESTMACRO_INTEGER 42
+#define TESTMACRO_STRING "Hello Preprocessor!"
+#define TESTMACRO_STRING_EXPANDED TESTMACRO_STRING
+
 #include <cwchar>
 
 enum {
diff --git a/src/callbacks.rs b/src/callbacks.rs
index 26f77338..81fe0c0e 100644
--- a/src/callbacks.rs
+++ b/src/callbacks.rs
@@ -35,6 +35,11 @@ pub trait ParseCallbacks: fmt::Debug + UnwindSafe {
         None
     }
 
+    /// This will be run on every string macro. The callback can not influence the further
+    /// treatment of the macro, but may use the value to generate additional code or configuration.
+    fn str_macro(&self, _name: &str, _value: &[u8]) {
+    }
+
     /// This function should return whether, given an enum variant
     /// name, and value, this enum variant will forcibly be a constant.
     fn enum_variant_behavior(
diff --git a/src/ir/var.rs b/src/ir/var.rs
index e29985ef..14f133fd 100644
--- a/src/ir/var.rs
+++ b/src/ir/var.rs
@@ -199,6 +199,9 @@ impl ClangSubItemParser for Var {
                             true,
                             ctx,
                         );
+                        if let Some(callbacks) = ctx.parse_callbacks() {
+                            callbacks.str_macro(&name, &val);
+                        }
                         (TypeKind::Pointer(char_ty), VarType::String(val))
                     }
                     EvalResult::Int(Wrapping(value)) => {