@__LINE__ (c.f @__FILE__)

[chtlp]

Hi, I want to get the file and line number (in the same spirit to __file__ and __file__ macro in C) for logging so I can quickly determine where the message was logged. show_backtrace() has this information, but is there a way of getting the fields without parsing the string, so I can use this efficiently for logging?

[tknopp]

@chtlp Its @__FILE__

Would be great if you could use the julia-user mailing list for these sort of questions. Thanks!

[pao]

Maling list link: https://groups.google.com/forum/#!forum/julia-users

[chtlp]

Thanks! I will ask in the group in the future. Is there a macro for the line number as well? @__LINE__ doesn't seem to work.

[StefanKarpinski]

Unfortunately, @__LINE__ is much harder to implement. We could convert this into a request for it.

[IainNZ]

I'm working through FactCheck.jl and it has the following code to get the line:

function getline()
    bt = backtrace()
    issecond = false
    for frame in bt
        lookup = ccall(:jl_lookup_code_address, Any, (Ptr{Void}, Int32), frame, 0)
        if lookup != ()
            if issecond
                return lookup[3]
            else
                issecond = true
            end
        end
    end
end

I thought I'd throw this in here in case someone needs a dirty hack in the mean time...

[mlubin]

Bump. In JuMP we do tons of code generation, and without this macro it's very hard to give useful backtraces and error messages.
Ref jump-dev/JuMP.jl#441

[ihnorton]

Another possible hack:

macro __LINE__()
    return :(unsafe_load(Ptr{Int}(cglobal(:jl_lineno))))
end

[vtjnash]

Another possible hack:

that hack assumes macro-expansion is occurring during parsing, which it often doesn't

[simonster]

@vtjnash doesn't @__FILE__ also assume that?

[vtjnash]

no, since @__FILE__ only works from Base.include

but also, yes, since @__FILE__ only works from Base.include