Concatenating BitStrings (Not Binaries) in Erlang

Question

How do you concatenate bitstrings. I mean bitstrings because I do not know the number of bytes to be a multiple of 8.

A = <<3:2>>
B = <<1:1>>
C = <<15:4>>

Solution should A|B|C should be <<127:7>>

Thanks

Answer 1

Construct the binary using /bitstring and all the previous values. Here's an example, running in the erlang shell:

1> A = <<3:2>>.
<<3:2>>
2> B = <<1:1>>.
<<1:1>>
3> C = <<15:4>>.
<<15:4>>
4> D = <<A/bitstring, B/bitstring, C/bitstring>>.
<<127:7>>