build(win): export extern symbols for use in FFI #22756

Makes `extern` variables accessible through ffi on Windows. Follow-up to #15999
neovim · Mar 23, 2023 · b028805 · b028805
1 parent 4e4203f
commit b028805
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diff --git a/src/nvim/main.c b/src/nvim/main.c
@@ -1,7 +1,12 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http:https://www.viva64.com
 
-#define EXTERN
+// Make sure extern symbols are exported on Windows
+#ifdef WIN32
+# define EXTERN __declspec(dllexport)
+#else
+# define EXTERN
+#endif
 #include <assert.h>
 #include <limits.h>
 #include <msgpack/pack.h>

diff --git a/test/functional/lua/ffi_spec.lua b/test/functional/lua/ffi_spec.lua
@@ -63,5 +63,14 @@ describe('ffi.cdef', function()
  nil
  )
  ]=])
+
+ -- Check that extern symbols are exported and accessible
+ eq(true, exec_lua[[
+ local ffi = require('ffi')
+
+ ffi.cdef('uint64_t display_tick;')
+
+ return ffi.C.display_tick >= 0
+ ]])
  end)
 end)