From da0bd64372163b4cd6fad3433fc1ab7f668ea9ef Mon Sep 17 00:00:00 2001
From: Lionel Henry <lionel.hry@gmail.com>
Date: Thu, 17 Nov 2022 16:42:15 +0100
Subject: [PATCH 1/2] Support hidden visibility

---
 src/Makevars | 1 +
 src/init.c   | 6 ++++++
 2 files changed, 7 insertions(+)
 create mode 100644 src/Makevars

diff --git a/src/Makevars b/src/Makevars
new file mode 100644
index 00000000..bf5eb423
--- /dev/null
+++ b/src/Makevars
@@ -0,0 +1 @@
+PKG_CFLAGS = $(C_VISIBILITY)
diff --git a/src/init.c b/src/init.c
index c43e4625..3f4c51fb 100644
--- a/src/init.c
+++ b/src/init.c
@@ -3,6 +3,11 @@
 #include <Rinternals.h>
 #include <stdlib.h> // for NULL
 
+// Compile with `C_VISIBILITY = -fvisibility=hidden` if you link to
+// this library
+#include <R_ext/Visibility.h>
+#define export attribute_visible extern
+
 /* .Call calls */
 extern SEXP glue_(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 extern SEXP trim_(SEXP);
@@ -12,6 +17,7 @@ static const R_CallMethodDef CallEntries[] = {
     {"trim_", (DL_FUNC)&trim_, 1},
     {NULL, NULL, 0}};
 
+export
 void R_init_glue(DllInfo* dll) {
   R_registerRoutines(dll, NULL, CallEntries, NULL, NULL);
   R_useDynamicSymbols(dll, FALSE);

From fa94a58ccd42be1c4af55e5b0391d199f6aa988f Mon Sep 17 00:00:00 2001
From: Jenny Bryan <jenny.f.bryan@gmail.com>
Date: Fri, 18 Nov 2022 08:41:49 -0800
Subject: [PATCH 2/2] Add NEWS bullet

---
 NEWS.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/NEWS.md b/NEWS.md
index bc7b59e2..374d5a01 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # glue (development version)
 
+* Add `$(C_VISIBILITY)` to compiler flags to hide internal symbols from the dll (#284 @lionel-).
+
 # glue 1.6.2
 
 * Modify a test for better forward compatibility with R.