From bee331e23dcfed961e64b68e392ca468dc3a1a65 Mon Sep 17 00:00:00 2001
From: Francois Perrad <francois.perrad@gadz.org>
Date: Fri, 24 Mar 2017 10:53:03 +0100
Subject: [PATCH] add lua_isyieldable() from 5.3

---
 src/lj_api.c | 5 +++++
 src/lua.h    | 3 +++
 2 files changed, 8 insertions(+)

diff --git a/src/lj_api.c b/src/lj_api.c
index e76cf8fe..1c40beba 100644
--- a/src/lj_api.c
+++ b/src/lj_api.c
@@ -1110,6 +1110,11 @@ LUALIB_API int luaL_callmeta(lua_State *L, int idx, const char *field)
 
 /* -- Coroutine yield and resume ------------------------------------------ */
 
+LUA_API int lua_isyieldable(lua_State *L)
+{
+  return cframe_canyield(L->cframe);
+}
+
 LUA_API int lua_yield(lua_State *L, int nresults)
 {
   void *cf = L->cframe;
diff --git a/src/lua.h b/src/lua.h
index 0c653f56..615e0e36 100644
--- a/src/lua.h
+++ b/src/lua.h
@@ -351,6 +351,9 @@ LUA_API int lua_loadx (lua_State *L, lua_Reader reader, void *dt,
 LUA_API const lua_Number *lua_version (lua_State *L);
 LUA_API void lua_copy (lua_State *L, int fromidx, int toidx);
 
+/* From Lua 5.3. */
+LUA_API int lua_isyieldable (lua_State *L);
+
 
 struct lua_Debug {
   int event;