c/c++中调用lua第一个例子

首先下载lua源码包，然后分别是make，make linux，make install

注意如果没有make install，那么在#include<lua.h>时，会报找不到lua.h文件的错误。

网上找到一段源码：

func.lua

--变量定义
width=1 ;
height=2 ;
--lua函数定义，实现加法
function sum(a,b)
    return a+b ;
end
--lua函数定义，实现字符串相加
function mystrcat(a,b)
    return a..b ;
end
--lua函数定义，通过调用c代码中的csum函数实现加法
function mysum(a,b)
    return csum(a,b) ;
end

test_lua.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
//lua头文件
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>


#define err_exit(num,fmt,args)  
    do{printf("[%s:%d]"fmt" ",__FILE__,__LINE__,##args);exit(num);} while(0)
#define err_return(num,fmt,args)  
    do{printf("[%s:%d]"fmt" ",__FILE__,__LINE__,##args);return(num);} while(0)

//lua中调用的c函数定义,实现加法
int csum(lua_State* l)
{
    int a = lua_tointeger(l,1) ;
    int b = lua_tointeger(l,2) ;
    lua_pushinteger(l,a+b) ;
    return 1 ;
}

int main(int argc,char** argv)
{
    lua_State * l = luaL_newstate() ;        //创建lua运行环境
    if ( l == NULL ) err_return(-1,"luaL_newstat() failed"); 
    int ret = 0 ;
    ret = luaL_loadfile(l,"func.lua") ;      //加载lua脚本文件
    if ( ret != 0 ) err_return(-1,"luaL_loadfile failed") ;
    ret = lua_pcall(l,0,0,0) ;
    if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(l,-1)) ;

    lua_getglobal(l,"width");              //获取lua中定义的变量
    lua_getglobal(l,"height");
    printf("height:%ld %ld ",lua_tointeger(l,-1),lua_tointeger(l,-2)) ;
    lua_pop(l,1) ;                        //恢复lua的栈

    int a = 11 ;
    int b = 12 ;
    lua_getglobal(l,"sum");               //调用lua中的函数sum
    lua_pushinteger(l,a) ;
    lua_pushinteger(l,b) ;
    ret = lua_pcall(l,2,1,0) ;
    if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(l,-1)) ;
    printf("sum:%d + %d = %ld ",a,b,lua_tointeger(l,-1)) ;
    lua_pop(l,1) ;

    const char str1[] = "hello" ;
    const char str2[] = "world" ;
    lua_getglobal(l,"mystrcat");          //调用lua中的函数mystrcat
    lua_pushstring(l,str1) ;
    lua_pushstring(l,str2) ;
    ret = lua_pcall(l,2,1,0) ;
    if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(l,-1)) ;
    printf("mystrcat:%s%s = %s ",str1,str2,lua_tostring(l,-1)) ;
    lua_pop(l,1) ;

    lua_pushcfunction(l,csum) ;         //注册在lua中使用的c函数
    lua_setglobal(l,"csum") ;           //绑定到lua中的名字csum

    lua_getglobal(l,"mysum");           //调用lua中的mysum函数，该函数调用本程序中定义的csum函数实现加法
    lua_pushinteger(l,a) ;
    lua_pushinteger(l,b) ;
    ret = lua_pcall(l,2,1,0) ;
    if ( ret != 0 ) err_return(-1,"lua_pcall failed:%s",lua_tostring(l,-1)) ;
    printf("mysum:%d + %d = %ld ",a,b,lua_tointeger(l,-1)) ;
    lua_pop(l,1) ;

    lua_close(l) ;                     //释放lua运行环境
    return 0 ;
}

直接编译，cc  test_lua.c，结果报错：

/tmp/ccuUFpHd.o: In function `csum':
test_lua.c:(.text+0x1b): undefined reference to `lua_tointegerx'
test_lua.c:(.text+0x31): undefined reference to `lua_tointegerx'
test_lua.c:(.text+0x46): undefined reference to `lua_pushinteger'
/tmp/ccuUFpHd.o: In function `main':
test_lua.c:(.text+0x62): undefined reference to `luaL_newstate'
test_lua.c:(.text+0xb1): undefined reference to `luaL_loadfilex'
test_lua.c:(.text+0x108): undefined reference to `lua_pcallk'
test_lua.c:(.text+0x124): undefined reference to `lua_tolstring'
test_lua.c:(.text+0x15a): undefined reference to `lua_getglobal'
test_lua.c:(.text+0x168): undefined reference to `lua_getglobal'
test_lua.c:(.text+0x17b): undefined reference to `lua_tointegerx'
test_lua.c:(.text+0x191): undefined reference to `lua_tointegerx'
test_lua.c:(.text+0x1b4): undefined reference to `lua_settop'
test_lua.c:(.text+0x1d0): undefined reference to `lua_getglobal'
test_lua.c:(.text+0x1df): undefined reference to `lua_pushinteger'
test_lua.c:(.text+0x1ee): undefined reference to `lua_pushinteger'
test_lua.c:(.text+0x212): undefined reference to `lua_pcallk'
test_lua.c:(.text+0x22e): undefined reference to `lua_tolstring'
test_lua.c:(.text+0x269): undefined reference to `lua_tointegerx'
test_lua.c:(.text+0x28f): undefined reference to `lua_settop'
test_lua.c:(.text+0x2c5): undefined reference to `lua_getglobal'
test_lua.c:(.text+0x2d2): undefined reference to `lua_pushstring'
test_lua.c:(.text+0x2df): undefined reference to `lua_pushstring'
test_lua.c:(.text+0x303): undefined reference to `lua_pcallk'
test_lua.c:(.text+0x31f): undefined reference to `lua_tolstring'
test_lua.c:(.text+0x35a): undefined reference to `lua_tolstring'
test_lua.c:(.text+0x382): undefined reference to `lua_settop'
test_lua.c:(.text+0x395): undefined reference to `lua_pushcclosure'
test_lua.c:(.text+0x3a3): undefined reference to `lua_setglobal'
test_lua.c:(.text+0x3b1): undefined reference to `lua_getglobal'
test_lua.c:(.text+0x3c0): undefined reference to `lua_pushinteger'
test_lua.c:(.text+0x3cf): undefined reference to `lua_pushinteger'
test_lua.c:(.text+0x3f3): undefined reference to `lua_pcallk'
test_lua.c:(.text+0x40f): undefined reference to `lua_tolstring'
test_lua.c:(.text+0x447): undefined reference to `lua_tointegerx'
test_lua.c:(.text+0x46d): undefined reference to `lua_settop'
test_lua.c:(.text+0x476): undefined reference to `lua_close'
collect2: ld returned 1 exit status

网上搜了下，需要加上lua静态库文件：

cc test_lua.c -llua，

这时之前报的错误都没了，又报新错误

/usr/local/lib/liblua.a(lobject.o): In function `luaO_arith':
lobject.c:(.text+0x5bf): undefined reference to `floor'
lobject.c:(.text+0x5f2): undefined reference to `pow'
/usr/local/lib/liblua.a(lvm.o): In function `luaV_execute':
lvm.c:(.text+0x23b9): undefined reference to `floor'
lvm.c:(.text+0x23f6): undefined reference to `pow'
collect2: ld returned 1 exit status

然后把命令改成：

cc test_lua.c -llua -lm

这时编译通过。