[9fans] how to output NUL byte from awk?

[9fans] how to output NUL byte from awk?

[dexen deVries]

awk(1) says, ``[s]tring constants are quoted " ", with the usual C escapes 
recognized within.'', but \0 seems to terminate internal string 
reprezentation...

so how do i output a real NUL byte?



-- 
dexen deVries

[[[↓][→]]]

Re: [9fans] how to output NUL byte from awk?

[Kurt H Maier]

Quoting dexen deVries <dexen.devries@gmail.com>:

> awk(1) says, ``[s]tring constants are quoted " ", with the usual C escapes
> recognized within.'', but \0 seems to terminate internal string
> reprezentation...
>
> so how do i output a real NUL byte?
>

Does printf not do this?

khm

Re: [9fans] how to output NUL byte from awk?

[dexen deVries]

On Tuesday 17 of September 2013 14:03:11 Kurt H Maier wrote:
> Quoting dexen deVries <dexen.devries@gmail.com>:
> > awk(1) says, ``[s]tring constants are quoted " ", with the usual C escapes
> > recognized within.'', but \0 seems to terminate internal string
> > reprezentation...
> >
> > so how do i output a real NUL byte?
>
> Does printf not do this?


thanks
i feel really dumb now ;-)


--
dx

Re: [9fans] how to output NUL byte from awk?

[erik quanstrom]

On Tue Sep 17 10:04:20 EDT 2013, khm@sciops.net wrote:
> Quoting dexen deVries <dexen.devries@gmail.com>:
>
> > awk(1) says, ``[s]tring constants are quoted " ", with the usual C escapes
> > recognized within.'', but \0 seems to terminate internal string
> > reprezentation...
> >
> > so how do i output a real NUL byte?
> >
>
> Does printf not do this?

no, awk's printf does not do that:
minooka;  awk 'BEGIN{printf "%c", utf(0)}' | wc
      0       0       0
minooka; awk 'BEGIN{printf "%.5s", "12\034567890"}' | xd -1
0000000  31 32 1c 35 36
minooka; awk 'BEGIN{printf "%.5s", "12\0\034567890"}' | xd -1
0000000  31 32

- erik

Re: [9fans] how to output NUL byte from awk?

[dexen deVries]

On Tuesday 17 of September 2013 12:50:07 erik quanstrom wrote:
> On Tue Sep 17 10:04:20 EDT 2013, khm@sciops.net wrote:
> > Quoting dexen deVries <dexen.devries@gmail.com>:
> > > awk(1) says, ``[s]tring constants are quoted " ", with the usual C
> > > escapes
> > > recognized within.'', but \0 seems to terminate internal string
> > > reprezentation...
> > > 
> > > so how do i output a real NUL byte?
> > 
> > Does printf not do this?
> 
> no, awk's printf does not do that:
> minooka;  awk 'BEGIN{printf "%c", utf(0)}' | wc
>       0       0       0
> minooka; awk 'BEGIN{printf "%.5s", "12\034567890"}' | xd -1
> 0000000  31 32 1c 35 36
> minooka; awk 'BEGIN{printf "%.5s", "12\0\034567890"}' | xd -1
> 0000000  31 32


printf "%c", 0


-- 
dexen deVries

[[[↓][→]]]

Take care of the luxuries and the necessities will take care of themselves.
                -- L. Long

Re: [9fans] how to output NUL byte from awk?

[arnold]

dexen deVries <dexen.devries@gmail.com> wrote:

> awk(1) says, ``[s]tring constants are quoted " ", with the usual C escapes
> recognized within.'', but \0 seems to terminate internal string
> reprezentation...
>
> so how do i output a real NUL byte?

Tooting my own horn (sorry)

	gawk 'BEGIN { printf("\0") }'

"No arbitrary limits" in action. :-)

Arnold

Re: [9fans] how to output NUL byte from awk?

[dexen deVries]

On Tuesday 17 of September 2013 12:50:07 erik quanstrom wrote:
> On Tue Sep 17 10:04:20 EDT 2013, khm@sciops.net wrote:
> > Quoting dexen deVries <dexen.devries@gmail.com>:
> > > awk(1) says, ``[s]tring constants are quoted " ", with the usual C
> > > escapes
> > > recognized within.'', but \0 seems to terminate internal string
> > > reprezentation...
> > >
> > > so how do i output a real NUL byte?
> >
> > Does printf not do this?
>
> no, awk's printf does not do that:
> minooka;  awk 'BEGIN{printf "%c", utf(0)}' | wc
>       0       0       0
> minooka; awk 'BEGIN{printf "%.5s", "12\034567890"}' | xd -1
> 0000000  31 32 1c 35 36
> minooka; awk 'BEGIN{printf "%.5s", "12\0\034567890"}' | xd -1
> 0000000  31 32



utf() is the problem, %c expect int, not string:

9 awk ' BEGIN { printf "%c", 0 } ' | 9 wc
      0       1       1


9 awk ' BEGIN { printf "X%cX", 0 } ' | 9 xd
0000000  58005800


--
dx

Re: [9fans] how to output NUL byte from awk?

[Kurt H Maier]

Quoting erik quanstrom <quanstro@quanstro.net>:

> On Tue Sep 17 10:04:20 EDT 2013, khm@sciops.net wrote:
>
> no, awk's printf does not do that:
> minooka;  awk 'BEGIN{printf "%c", utf(0)}' | wc

not if you ask it to convert '0' to unicode and then covert
the unicode value to a char, no.   I'm almost positive if you
tell it to cast 0 (the number) to char and print it, it will
give you a null byte.

khm

Re: [9fans] how to output NUL byte from awk?

[cinap_lenrek]

confirmed.

--
cinap

Re: [9fans] how to output NUL byte from awk?

[Florian Limberger]

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On Tue, 17 Sep 2013 15:47:17 +0200
dexen deVries <dexen.devries@gmail.com> wrote:

> awk(1) says, ``[s]tring constants are quoted " ", with the usual C
> escapes recognized within.'', but \0 seems to terminate internal
> string reprezentation...
> 
> so how do i output a real NUL byte?

I  know this is not very constructive and may seem like a dumb question,
but isn’t \0 the end marker for C strings?  So this behaviour  might  be
expected?


-flo

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Re: [9fans] how to output NUL byte from awk?

[Bruce Ellis]

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spot on. that's why:

printf "%c", 0

works, move on now.


On 18 September 2013 17:24, Florian Limberger
<flo@snakeoilproductions.net>wrote:

> On Tue, 17 Sep 2013 15:47:17 +0200
> dexen deVries <dexen.devries@gmail.com> wrote:
>
> > awk(1) says, ``[s]tring constants are quoted " ", with the usual C
> > escapes recognized within.'', but \0 seems to terminate internal
> > string reprezentation...
> >
> > so how do i output a real NUL byte?
>
> I  know this is not very constructive and may seem like a dumb question,
> but isn’t \0 the end marker for C strings?  So this behaviour  might  be
> expected?
>
>
> -flo
>

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