diff --git a/NAM/get_dsp.h b/NAM/get_dsp.h
index 4783d71e..a49da706 100644
--- a/NAM/get_dsp.h
+++ b/NAM/get_dsp.h
@@ -26,10 +26,14 @@ class IVersionSupportChecker
 class Version
 {
 public:
+  // Brace-init the members rather than `major(major)`: <sys/types.h> (FreeBSD)
+  // and <sys/sysmacros.h> (glibc) define major() and minor() as function-like
+  // macros that stay macros in C++, and they expand on `major(`, breaking this
+  // header for any consumer that includes them first. `major{` does not expand.
   Version(int major, int minor, int patch)
-  : major(major)
-  , minor(minor)
-  , patch(patch)
+  : major{major}
+  , minor{minor}
+  , patch{patch}
   {
   }
 
diff --git a/tools/run_tests.cpp b/tools/run_tests.cpp
index ee827818..2895107d 100644
--- a/tools/run_tests.cpp
+++ b/tools/run_tests.cpp
@@ -2,6 +2,9 @@
 // See the GitHub Action for a demo of how to build and run tests.
 
 #include <iostream>
+// Must come first: it checks that NAM/get_dsp.h parses while major()/minor() are
+// macros, which only means anything if no earlier test has already included it.
+#include "test/test_get_dsp_sys_types.cpp"
 #include "test/test_activations.cpp"
 #include "test/test_activations_realtime_safe.cpp"
 #include "test/test_conv1d.cpp"
@@ -44,6 +47,7 @@
 int main()
 {
   std::cout << "Running tests..." << std::endl;
+  test_get_dsp_sys_types::test_version_builds_with_major_minor_macros_defined();
   test_get_dsp_wav::test_formats_and_configuration();
   test_get_dsp_wav::test_invalid_files();
   // TODO Automatically loop, catch exceptions, log results
diff --git a/tools/test/test_get_dsp_sys_types.cpp b/tools/test/test_get_dsp_sys_types.cpp
new file mode 100644
index 00000000..2ac7a6a0
--- /dev/null
+++ b/tools/test/test_get_dsp_sys_types.cpp
@@ -0,0 +1,45 @@
+// Regression test for issue #304.
+//
+// FreeBSD's <sys/types.h> and glibc's <sys/sysmacros.h> define major() and
+// minor() as function-like macros, and unlike Apple's headers they keep them as
+// macros in C++. Any consumer that includes one of those before NAM/get_dsp.h
+// used to fail to compile, because nam::Version's member-initializer list read
+// `major(major)` and the macro expanded.
+//
+// The macros are defined here rather than by including <sys/types.h> so the
+// test reproduces the FreeBSD/glibc preprocessor state on every platform. They
+// must go after get_dsp.h's dependency closure -- expanding them inside libc++'s
+// own headers is a different, unrelated failure -- and are undefined at the end
+// so they do not leak into the other tests included by run_tests.cpp.
+
+#include <cassert>
+#include <memory>
+#include <optional>
+#include <string>
+#include <vector>
+
+#include "NAM/dsp.h"
+#include "NAM/nam_file.h"
+
+#define major(x) ((int)(((unsigned)(x) >> 24) & 0xff))
+#define minor(x) ((int)((x) & 0xffffff))
+
+#include "NAM/get_dsp.h"
+
+#undef major
+#undef minor
+
+namespace test_get_dsp_sys_types
+{
+// Compiling this translation unit at all is the test; the assertions just keep
+// the constructor from being optimized away and confirm the fields still land
+// in the right order.
+void test_version_builds_with_major_minor_macros_defined()
+{
+  const nam::Version version(1, 2, 3);
+  assert(version.major == 1);
+  assert(version.minor == 2);
+  assert(version.patch == 3);
+  assert(version.toString() == "1.2.3");
+}
+} // namespace test_get_dsp_sys_types