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Questions tagged [lua-api]

Anything related to Lua C Application Programming Interface (Lua C-API).

Lua has been designed to be easily integrated with C applications, thus it provides a rich API to interact with C code, which is called the Lua C-API.

The Lua C-API can be used both for:

  • enabling the Lua engine to communicate with an host application (the application which embeds the engine), and

  • enabling library code for Lua written in C to communicate with the Lua engine that loads the library.

197 questions
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Test if Lua number is integer or float

In my C++ program, I need to know if a Lua variable is an integer number or a floating-point number. The C API provides lua_isnumber() but this function does not distinguish between int/float/double. So far I have worked around this by using…
glampert
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Lua API push userdata

I'm trying to give a scripting ability to my component system. Of couse each component has a field "parent" which holds access to the parent Actor. I can write the code so I can access my C++ methods from Lua, but I got stuck when I want to return…
RobeeZ
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How can I get list of all table names in .lua script using Lua C API?

I have a lua file which looks like this: tableA = {…} tableB = {…} tableC = {…} I want to get std::vector which will contain the names of all tables defined in file: {"tableA", "tableB", "tableC"} How can I do this with Lua C API?
user999040
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Pointer to number

It seems like there's know such thing as a reference to a number/boolean/lightuserdata in Lua. However, what would be the easiest way to set a global in Lua that points to a C++ native type (e.g. float) and have it update automatically when I change…
TravisG
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Lua Registry in required modules

Are keys set in the registry of a temporary state that's accessed in a module int luaopen_foo(lua_State*) adopted in the registry of the calling state? For example, let's say we have this module: int luaopen_foo(lua_State* state) { …
Appleshell
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Getting a “pointer” to a Lua function stored in C

In the Lua C API I can store a number or a string from the stack with lua_tostring(). How can a “reference” (if that is the correct term) to a Lua function be passed to C through the Lua API? So it can be called later from C, with lua_call(),…
user1598585
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Error loading module undefined symbol: luaL_setfuncs

I am trying to create a C module to be called from a lua script. I am working on debian linux. I am using mysql-proxy and lua 5.2. I have created (copied from a tutorial) some example functions to be called. The loader is defined like this: int…
jordi
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Details about function arguments through Lua C API

if I call a function foo(t[1]) through the C API, can I in any way see what table and what index is as argument, in this case t and 1? The problem at hand is a function move_card(card, table_slots[0]) where I move a card from one slot on a game area…
Olle Härstedt
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Lua C API - mapping a property to a function

Is it possible to push a function as a property in Lua? Right now, I can have Get/Set functions by pushing them as fields like so: lua_pushcfunction(L,L_Getter); lua_setfield(L, -2, "GetValue"); lua_pushcfunction(L,L_Setter); lua_setfield(L,…
Grapes
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How do I set, via the lua C API, the environment table for a chunk of lua code prior to running it?

The interface for my game engine is built using a markup language and Lua, similar to HTML and javascript. As such, visual elements will have handlers for UI events such as a mouse move or click, and each time a handler is to be run, the engine…
jorgander
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Moving a lua table in C api

I'm attempting to move a table to another table using the lua C api. For instance, I have a table with this structure: a[b][c][d][e] = value I want to move table d this to be under a[b], which I could accomplish in Lua like: a[b][d] =…
Chrismit
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Can I initialize and work with two Lua buffers at the same time?

Given that the LuaL_Buffer object: "During its normal operation, a string buffer uses a variable number of stack slots", I don't understand how two luaL_Buffer objects can be used at the same time. Will they each assume the state of the stack is as…
Paul
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Port lua (5.2-5.4) C++ connection to lua 5.1?

I'm working on the mGBA project (https://github.com/mgba-emu/mgba) and I'm trying to fix some problems regarding the scripting API and Lua 5.1. The project has the following functions: Load the Lua script: bool _luaLoad(struct mScriptEngineContext*…
Nuive
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How to manage vector of pointers in C++ where pointer is allocated by Lua

In the simple 2D Game Engine I am working. I want to define and script my entities using Lua and do all the heavy work in C++ (rendering, physics, etc.) To do this I have basic Entity class: class Entity { public: Entity() { …
kaktusas2598
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How to get number of entries from a lua_getglobal and name of entries in c code

I would like to know if there is any way for me to get the number of entries in a lua_getglobal and get the name of each entry I need to know why I need to use a loop to apply lua definitions in my C code: example moon code: Mytbl = { var = { …
alberto silva
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