From fae5bf811e75e94d6ee89f1957cd4e224ed384e2 Mon Sep 17 00:00:00 2001
From: Mark Winkel <mwinkel@psfc.mit.edu>
Date: Wed, 23 Aug 2023 17:13:01 -0400
Subject: [PATCH] MacOS now has working OFD locks

---
 treeshr/RemoteAccess.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/treeshr/RemoteAccess.c b/treeshr/RemoteAccess.c
index ea3f156a2f..1e4786ef04 100644
--- a/treeshr/RemoteAccess.c
+++ b/treeshr/RemoteAccess.c
@@ -24,6 +24,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 #include <mdsplus/mdsconfig.h>
+#include <mdsplus/mdsplus.h>
 #ifdef _WIN32
 #include <winsock2.h>
 #include <windows.h>
@@ -39,11 +40,23 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // # define flock lx_flock
 // # include <linux/fcntl.h>
 // # undef flock
+
 #ifndef F_OFD_SETLK
+#ifdef _MACOSX
+// Open File Descriptor (OFD) locks have existed as a private / undocumented
+// feature in MacOS releases since 2015.  For more details, refer to the
+// comments at the end of Issue #2599 and the earlier PRs #2163 and #2198.
+#define F_OFD_GETLK 92
+#define F_OFD_SETLK 90
+#define F_OFD_SETLKW 91
+#else
+// The usual defines for Linux
 #define F_OFD_GETLK 36
 #define F_OFD_SETLK 37
 #define F_OFD_SETLKW 38
 #endif
+#endif
+
 #endif
 #include <ctype.h>
 #include <errno.h>