ltrace

Two implementations

ltrace.lua pure lua

src/ltrace.c pure C, see src/test.lua, easy to use, but without table dumping, just call ltrace.traceback()

Description

How To Debug With Lua, Lots of print?

We don't need print() any more!

Instead of debug.traceback(), this lib gives you more infomations of every lua call stack frame.

lua Support

luajit Support(with param names for function output)

In C++ or Java, you just use

try {
	// statements
} catch(e) {
	// statements
}

while in Lua, you need xpcall like this:

function TryFunc()
	-- statement
end

function CatchFunc(err)
	-- statement
	print(err)
	print(debug.traceback())
end

xpcall(TryFunc, CatchFunc)

in CatchFunc, we just call debug.traceback() to get stackframe to locate your mistake.

ltrace.getfulltrace() will show you every variable(name and value) of each frame(with function name, filename and linenum) in lua call stack

Output Format

Variables show in each frame are sorted by declaration order.

If you are using luajit or lua 5.2 later, param names will be showed in brackets. See Example

frameidx @filepath.lua:linenum in <functionName()>
	local_variable_name1:variable_value
	local_variable_name2:variable_value
	...

How To Use?

local ltrace = require "ltrace"

function errordump(errstr)
	io.stderr:write(errstr .. "\n")
end

function main()
	-- do call
end

xpcall(main, function(err)
	errordump(err)
	errordump(ltrace.getfulltrace())
end)

Example

test.lua

this is a sample of err catching dumping (use luajit or lua 5.2 or later)

test.lua:17: attempt to perform arithmetic on global 'nondefined_var' (a nil value)
0 @test.lua:31 in <__add(err)>
        err:"test.lua:17: attempt to perform arithmetic on global 'nondefined_var' (a nil value)"
        (*temporary):<file (0x7fff734894a0)>
1 @test.lua:17 in <a(arg1, arg2)>
        arg1:"xx"
        arg2:"yy"
        a000:false
        a111:111
        a222:"222"
        a333:"333"
        f:<function: 0x00050568>
        t:{[1]=1, [2]=2, [3]=45, [4]=5, [5]=4, [6]=672, ff=<function: 0x000506a0>, s="12", submap={[1]="aa", [2]="bb"}}
        (*temporary):"attempt to perform arithmetic on global 'nondefined_var' (a nil value)"
2 @test.lua:24 in <b()>
        bt:{[1]=1, [2]=5, [3]=256, [4]="234", a={b="v"}}
        bs:"this is a string"
        bn:4234239
3 @test.lua:28 

4[C] : in <xpcall>
5[C] : in <main>
6[C] : in <C>