From: Tadeusz Bochan <tad@...>
Date: 2011-02-24T10:41:15+09:00
Subject: Re: Console output formatting

The 'dl' package is certainly one of the most useful Ruby libs out there
and avery clever piece of work. It's a shame it hasn't been 
documented/supported very well.

The following works on 1.8.6 and I believe it doesn't in 1.9.
No doubt some gurus will be able to clarify.

require 'dl'
clib = DL.dlopen("/usr/lib/libc.sl")
strlen=clib['strlen',"IS"]
message = "Hello\n"
p strlen[message].first => 6

The above is calling strlen which has simple parameters,
an 'I'nteger return, and a 'S'tring by reference.
(It's too late in the night to do scanf, and the Standard library
already does scanf)

You can use this for any C routine, as long as you get the
parameter prototype string setup correctly.

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