It works! Thanks. J

 

 

De: Johny Mattsson [mailto:[email protected]] 
Enviada: sexta-feira, 29 de Julho de 2011 00:25
Para: Carlos Rodrigues
Cc: tinyos-help
Assunto: Re: [Tinyos-help] Create a random value during make

 

On Thu, Jul 28, 2011 at 11:20 PM, Carlos Rodrigues <[email protected]> wrote:

It is possible create a random value during a make? For example in Makefile
have something like this:
CFLAGS += -DVALUE_RANDOM

Assuming you're on a *nix system (and using GNU make, but that should be a
given), you could do something like:

1) For low randomness (but maybe sufficient for you), just use a process ID:
CFLAGS+= -DMY_RANDOM_VALUE=$(shell echo $$$$)

or

2) For much better randomness, grab a couple of bytes from /dev/random, like
so:
CFLAGS+= -DMY_RANDOM_VALUE=$(shell dd if=/dev/random bs=2 count=1
2>/dev/null | od -tu2 | awk '{print $$2}')

There are probably shorter/neater way to do the latter, but I'll leave that
as the traditional exercise for the reader.

Cheers,
/Johny

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