[erlang-questions] Port Driver, outputv, binaries.

Björn Gustavsson <>
Thu Dec 10 11:37:02 CET 2009


On Thu, Dec 10, 2009 at 11:12 AM, Tony Rogvall <> wrote:
>        This type of binary is constructed when data is less than 64 bytes (may be changed!)

Yes, it may theoretically be changed, but we have no plans to do so
because we have
no good reason to change it and it would break code that depends on the value.

> The shell actually constructed a SubBin pointing to a
> ProcBin maybe some one at the OTP team knows why!?

Yes. :-)

The reason is that the eval_bits module that the shell uses
to evaluate binary syntax expressions appends to a binary,
and appending to a binary always force a reference-counted
binary to be created.

The different kind of binaries are described in the Efficiency Guide:

http://www.erlang.org/doc/efficiency_guide/binaryhandling.html

-- 
Björn Gustavsson, Erlang/OTP, Ericsson AB


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