如何将全局值从C传递给LUA？ [英] How to pass a global value from C to LUA?

问题描述

最近我尝试在我的C应用程序中嵌入LUA，现在我想要做的是我有一个值（Session_ID），我想从C函数传递给LUA脚本，以便LUA可以使用它脚本在C中调用一个函数。

在C中加载LUA脚本并运行它（使用lua_pcall）没有问题，我也没问题从LUA里面的C函数，我现在的问题是来回传递全局变量。

例如：

  session_id = 1; 
 luabc_sz = rlen; 
 result = lua_load（L，luaByteCodeReader，file，script，bt）; 
 if（lua_pcall（L，0，0，0）！= 0）
  

file是包含LUA脚本（script.lua）的数组。

在Lua side script.lua）：

  printStart
 for i = 1,10 do 
 print（i，** session_id **）
 end 
 printEnd
  

print 被我自己的函数覆盖，我想将 session_id 传递给它。
所以完整的场景是我在c函数中有 session_id ，我想将它传递给LUA脚本，稍后它将使用它来调用用C编写的打印函数。

有任何帮助：）？

解决方案

session_id 放入堆栈，并在 pcall 时将其传递到脚本中。例如：

  // ... 
 result = lua_load（L，luaByteCodeReader，file，script， BT）; 
 lua_pushinteger（L，session_id）; 
 if（lua_pcall（L，1,0,0）！= 0）
 // ... 
  

让脚本像访问它一样：

 本地session_id = ... 
 print 开始
 i = 1，10 
 print（i，session_id）
结束
 print结束
  

另一种方法，虽然不太吸引人，但是在lua的全球环境中添加 session_id ：

  // ... 
 result = lua_load（L，luaByteCodeReader，file，script，bt）; 
 lua_pushinteger（L，session_id）; 
 lua_setglobal（L，session_id）; 
 if（lua_pcall（L，0，0，0）！= 0）
 //其余的代码
  

script.lua 现在可以通过 session_id 访问该会话值。

Recently I manged to embed LUA in my C application, what I'm trying to do now is thatI have a value (Session_ID) I want to pass from C function to a LUA script, so that it can be used by LUA script to Call a function back in C.

I have no problem loading LUA script in C and running it (using lua_pcall), and I have no problem as well to call the C function from inside LUA, my current problem is passing global variable back and forth.

For example:

At C side (test.c):

session_id = 1;
luabc_sz = rlen;
result = lua_load(L, luaByteCodeReader, file, "script", "bt");      
if( lua_pcall(L, 0, 0, 0) != 0 )

Where file is the array containing the LUA script (script.lua).

At Lua side script.lua):

print "Start"
for i=1,10 do
  print(i, **session_id**)
end
print "End"

"print" is overwritten by my own function, and I want to pas the session_id to it. So the complete scenario is that I have the session_id in the c function, which I want to pass to the LUA script which will use it later to call the print function which is written in C.

Any help with that :)?

解决方案

Just push session_id onto the stack and pass it into the script when you pcall it. Something like:

// ...
result = lua_load(L, luaByteCodeReader, file, "script", "bt");
lua_pushinteger(L, session_id);
if( lua_pcall(L, 1, 0, 0) != 0 )
// ...

Have your script access it like:

local session_id = ...
print "Start"
for i = 1, 10 do
  print(i, session_id)
end
print "End"

Another alternative, though less appealing, is to add session_id to lua's global environment:

// ...
result = lua_load(L, luaByteCodeReader, file, "script", "bt");
lua_pushinteger(L, session_id);
lua_setglobal(L, "session_id");
if( lua_pcall(L, 0, 0, 0) != 0 )
// rest of your code

script.lua can now access that session value via session_id.

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