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Lua调试:getinfo详解

  getinfo是调试Lua程序时一个很重要很常见的函数,主要用于获取函数调用的基本信息。这个函数的难点在于各个参数的含义。下面一一介绍。

一、函数简介:

1.原型:getinfo(level, arg)

2.调用:debug.getinfo(level, arg)

3.返回值:返回一个包含函数信息的tabletable的内容由参数arg决定,包含哪个函数的信息由level决定.

4.参数解释:

  (1)level:函数调用的层级,表示要输出哪个函数的信息。

      (0:getinfo自身,1:调用getinfo的函数f1,2:调用f1的函数f2,...以此类推。f1, f2, ...也可能不是函数,而是在文件中直接调用getinfo)

  (2)arg:该参数是一个字符串,其中每个字符代表一组字段,用于指定希望获取哪些信息,可为 "n","S","l","u","f","L" 中的一个或他们的组合

    【注意区分大小写

    <英文看不懂没关系,我简单解释下,加黑的表示返回的table包含的内容,即函数信息>   

    n‘: fills in the field name and namewhat

    S‘: fills in the fields sourcelinedefinedlastlinedefinedwhat, and short_src;(source)

    l‘: fills in the field currentline

    u‘: fills in the field nups;

    f‘: pushes onto the stack the function that is running at the given level; ->func

    L‘: pushes onto the stack a table whose indices are the numbers of the lines that are valid on the function. (A valid line is a line with some       associated code, that is, a line where you can put a break point. Non-valid lines include empty lines and comments.) ->activelines

    name:函数名, namewhat:函数类型(field, upvalue, global),what:函数类型(Lua, C, main),

     short_src, source:函数所属的文件名,  linedefined, lastlinedefined:函数定义的起始和结束行号,

     currentline:上级(level - 1)函数被调用的行号,nups: 函数的upvalue值的个数, 

       func:函数本身, activelines:一个包含行号的table,可理解为该函数运行的代码的行号

  (如果还不是很明白,可以看下面的示例,也可以自己运行一下代码)

二、示例

假设一个文件luatest4.lua包含如下代码:

local args = {"n","S","l","u","f","L"}
local function f1()
  for level =0,3 do --不同级别
    print("level================", level)
    for k, v in ipairs(args) do --不同参数
      print("arg======", v)
      local fInfo = debug.getinfo(level, v)
      for key, val in pairs(fInfo) do
        print("key, val==", key, val)
      end
    end
  end
end

local function f2()
  print("f1=====", f1)
  f1()
end

function main()
  print("f2=====", f2)
  f2()
end
print("main======", main)
main()

--========运行以上代码,结果如下(win7上测试的)======

main====== function: 0073D128
f2===== function: 0073D108
f1===== function: 0073D0E8
level================ 0
arg====== n
key, val== name getinfo
key, val== namewhat field
arg====== S
key, val== source =[C]
key, val== what C
key, val== lastlinedefined -1
key, val== linedefined -1
key, val== short_src [C]
arg====== l
key, val== currentline -1
arg====== u
key, val== nups 0
arg====== f
key, val== func function: 0073AF70
arg====== L
level================ 1
arg====== n
key, val== name f1
key, val== namewhat upvalue
arg====== S
key, val== source @luatest4.lua
key, val== what Lua
key, val== lastlinedefined 13
key, val== linedefined 2
key, val== short_src luatest4.lua
arg====== l
key, val== currentline 7
arg====== u
key, val== nups 1
arg====== f
key, val== func function: 0073D0E8
arg====== L
key, val== activelines table: 0073BC78
level================ 2
arg====== n
key, val== name f2
key, val== namewhat upvalue
arg====== S
key, val== source @luatest4.lua
key, val== what Lua
key, val== lastlinedefined 18
key, val== linedefined 15
key, val== short_src luatest4.lua
arg====== l
key, val== currentline 17
arg====== u
key, val== nups 1
arg====== f
key, val== func function: 0073D108
arg====== L
key, val== activelines table: 0073BDE0
level================ 3
arg====== n
key, val== name main
key, val== namewhat global
arg====== S
key, val== source @luatest4.lua
key, val== what Lua
key, val== lastlinedefined 23
key, val== linedefined 20
key, val== short_src luatest4.lua
arg====== l
key, val== currentline 22
arg====== u
key, val== nups 1
arg====== f
key, val== func function: 0073D128
arg====== L
key, val== activelines table: 0073EA78

--===============================

看完这个示例后,大家应该对getinfo有所了解了吧。

 

Lua调试:getinfo详解