[julia-users] Re: weird read behavior

[Ariel Keselman]

You can test the actual function used with the @which macro. In the 1st 
example
it calls into io.jl line 118 (at least as of version 0.3):

read{T}(s::IO, t::Type{T}, d1::Int, dims::Int...) =
    read(s, t, tuple(d1,dims...))


this calls into io.jl line 123:

read{T}(s::IO, ::Type{T}, dims::Dims) = read!(s, Array(T, dims))


this calls into iostream.jl line 191:

function read!{T}(s::IOStream, a::Array{T})
    if isbits(T)
        nb = length(a)*sizeof(T)
        if ccall(:ios_readall, Uint,
                 (Ptr{Void}, Ptr{Void}, Uint), s.ios, a, nb) < nb
            throw(EOFError())
        end
    else
        invoke(read!, (IO, Array), s, a)
    end
    a
end

*there is no loop!*

Also in the first version, the list comprehension in the loop is being 
created each iteration.

maybe try using istead:

seek(position(stream)+4)

so you just move forward without creating a list.