[zeromq-dev] ZMQ appends weird characters to message

[Thomas Rodgers]

You will need cast ackMessage.data() to char* (e.g.
static_cast<char*>(ackMessage.data())) for that to work.


On Mon, Sep 15, 2014 at 10:52 AM, Thomas Rodgers <rodgert at twrodgers.com>
wrote:

> You can do something like -
>
> zmq::message_t ackMessage(message.size());
> std::copy_n(message.data(), message.size(), ackMessage.data());
>
> This constructor form will cause the message to allocate it's own storage
> (and thus free it appropriately), you then copy the contents of your string
> into the storage managed by the message.
>
>
> On Mon, Sep 15, 2014 at 10:44 AM, Dávid Kaya <mail at davidkaya.sk> wrote:
>
>> Oh thanks a lot, didn't know this. So the correct way would be to have
>> one pointer to message_t as a member of my class and before every send()
>> I should rebuild it and delete it manually when I am done with the
>> socket, right? Or should I have (message_t*) for every message I use?
>>
>> On 15.09.2014 19:30, Thomas Rodgers wrote:
>> > Message goes out of scope, destructor called, receiving side is
>> > getting a pointer to a free'd heap block.
>> >
>> > On Mon, Sep 15, 2014 at 10:27 AM, Dávid Kaya  wrote:
>> >
>> >> Here is that function: http://pastebin.com/AgUuDqqK [1] .
>> >>
>> >> On 15.09.2014 19:19, gonzalo diethelm wrote:
>> >> > Without seeing any actual code, it is impossible to say.
>> >> >
>> >> > --
>> >> > Gonzalo Diethelm
>> >> > DCV Chile
>> >> >
>> >> >> -----Original Message-----
>> >> >> From: zeromq-dev-bounces at lists.zeromq.org [2]
>> >> [mailto:zeromq-dev- [3]
>> >> >> bounces at lists.zeromq.org [4]] On Behalf Of Dávid Kaya
>> >> >> Sent: Monday, September 15, 2014 2:18 PM
>> >> >> To: ZeroMQ development list
>> >> >> Subject: Re: [zeromq-dev] ZMQ appends weird characters to
>> >> message
>> >> >>
>> >> >> If it would be because of memory, the std::string.replace()
>> >> would
>> >> >> not fix,
>> >> >> would it? Everything is done in one function, I don't think this
>> >> is
>> >> >> the problem.
>> >> >>
>> >> >>
>> >> >> On 15.09.2014 19:11, gonzalo diethelm wrote:
>> >> >> > That usually happens... Try to focus on the differences
>> >> between
>> >> >> your
>> >> >> > short example and your real code.
>> >> >> >
>> >> >> > One point to focus on could be memory management: are you sure
>> >> the
>> >> >> > messages you are sending are actually surviving until they get
>> >> >> sent?
>> >> >> > A
>> >> >> > simple wrong way to manage this would be putting your messages
>> >> in
>> >> >> an
>> >> >> > automatic variable that gets overwritten when you leave the
>> >> >> function
>> >> >> > that sends the message. Another wrong way would be using a
>> >> static
>> >> >> > buffer for your messages, that gets overwritten with each
>> >> message.
>> >> >> >
>> >> >> > HTH.
>> >> >> >
>> >> >> > --
>> >> >> > Gonzalo Diethelm
>> >> >> > DCV Chile
>> >> >> >
>> >> >> >> -----Original Message-----
>> >> >> >> From: zeromq-dev-bounces at lists.zeromq.org [5]
>> >> [mailto:zeromq-dev- [6]
>> >> >> >> bounces at lists.zeromq.org [7]] On Behalf Of Dávid Kaya
>> >> >> >> Sent: Monday, September 15, 2014 2:02 PM
>> >> >> >> To: ZeroMQ development list
>> >> >> >> Subject: Re: [zeromq-dev] ZMQ appends weird characters to
>> >> message
>> >> >> >>
>> >> >> >> Well I tried to recreate the problem but it works as intended
>> >> in
>> >> >> my
>> >> >> >> short example. I really don't know where could be the problem
>> >> >> since I
>> >> >> >> am doing it exactly the same way in my example as in my
>> >> >> application.
>> >> >> >> Maybe the problem is in the std::string, because when I use
>> >> >> >> std::string.replace() to replace some characters in the URL
>> >> then
>> >> >> it
>> >> >> >> works fine.
>> >> >> >> But when I dont use it and append the URL to "success:"
>> >> >> >> message right away, then it does not work. So maybe
>> >> >> >> std::string.replace() somehow fixes the string when it
>> >> rearranges
>> >> >> it.
>> >> >> >> The first problem with "login" was because I wasn't using
>> >> size()
>> >> >> in
>> >> >> >> string constructor.
>> >> >> >>
>> >> >> >> David
>> >> >> >>
>> >> >> >> On 15.09.2014 17:56, gonzalo diethelm wrote:
>> >> >> >> > Please create a short (as short as possible) example that
>> >> shows
>> >> >> >> this
>> >> >> >> > symptom, and post it to the list.
>> >> >> >> >
>> >> >> >> > --
>> >> >> >> > Gonzalo Diethelm
>> >> >> >> > DCV Chile
>> >> >> >> >
>> >> >> >> >> -----Original Message-----
>> >> >> >> >> From: zeromq-dev-bounces at lists.zeromq.org [8]
>> >> [mailto:zeromq-dev- [9]
>> >> >> >> >> bounces at lists.zeromq.org [10]] On Behalf Of Dávid Kaya
>> >> >> >> >> Sent: Monday, September 15, 2014 12:39 PM
>> >> >> >> >> To: ZeroMQ development list
>> >> >> >> >> Subject: Re: [zeromq-dev] ZMQ appends weird characters to
>> >> >> message
>> >> >> >> >>
>> >> >> >> >> Yes, I've printed that message. There can't be any NULL
>> >> byte
>> >> >> >> there.
>> >> >> >> >> It is string
>> >> >> >> >> "success:" appended with url. It is normal url like
>> >> >> >> >> "http://example.org/path/to/jsp?lang=en_US?session=
>> >> [11]"session id
>> >> >> >> here".
>> >> >> >> >> That session ID contains numbers, characters and dashes.
>> >> >> >> >>
>> >> >> >> >>
>> >> >> >> >> On 15.09.2014 17:30, gonzalo diethelm wrote:
>> >> >> >> >> > No, this is not a (known) limitation. Did you print
>> >> exactly
>> >> >> >> what
>> >> >> >> >> you
>> >> >> >> >> > are sending and what you are receiving? My guess is you
>> >> are
>> >> >> >> >> putting a
>> >> >> >> >> > null byte in the middle of what you are sending.
>> >> >> >> >> >
>> >> >> >> >> > --
>> >> >> >> >> > Gonzalo Diethelm
>> >> >> >> >> > DCV Chile
>> >> >> >> >> >
>> >> >> >> >> >> -----Original Message-----
>> >> >> >> >> >> From: zeromq-dev-bounces at lists.zeromq.org [12]
>> >> >> [mailto:zeromq-dev- [13]
>> >> >> >> >> >> bounces at lists.zeromq.org [14]] On Behalf Of Dávid Kaya
>> >> >> >> >> >> Sent: Monday, September 15, 2014 12:21 PM
>> >> >> >> >> >> To: zeromq-dev at lists.zeromq.org [15]
>> >> >> >> >> >> Subject: Re: [zeromq-dev] ZMQ appends weird characters
>> >> to
>> >> >> >> message
>> >> >> >> >> >>
>> >> >> >> >> >> Well, I've printed out size and it is correct. I've
>> >> also
>> >> >> >> >> shortened
>> >> >> >> >> >> the message by 5 characters and it stopped cutting off
>> >> the
>> >> >> >> last
>> >> >> >> >> >> characters (atleast I think it stopped, tried 15 times
>> >> and
>> >> >> it
>> >> >> >> >> came
>> >> >> >> >> >> correct every time). So I think the problem was in the
>> >> >> length
>> >> >> >> of
>> >> >> >> >> the
>> >> >> >> >> >> message. I don't know if it is a bug in ZMQ or system
>> >> >> >> limitation
>> >> >> >> >> of
>> >> >> >> >> >> socket files?
>> >> >> >> >> >>
>> >> >> >> >> >> David
>> >> >> >> >> >>
>> >> >> >> >> >>
>> >> >> >> >> >> On 15.09.2014 16:47, gonzalo diethelm wrote:
>> >> >> >> >> >> > Good point. Forgot about the specific details for
>> >> that
>> >> >> C++
>> >> >> >> >> >> > constructor. The null byte should not be required.
>> >> >> >> >> >> >
>> >> >> >> >> >> > As Tom points out, you should print out what you are
>> >> >> sending
>> >> >> >> >> and
>> >> >> >> >> >> > receiving (contents and length) and make sure it
>> >> makes
>> >> >> >> sense.
>> >> >> >> >> >> >
>> >> >> >> >> >> > HTH.
>> >> >> >> >> >> >
>> >> >> >> >> >> > --
>> >> >> >> >> >> > Gonzalo Diethelm
>> >> >> >> >> >> > DCV Chile
>> >> >> >> >> >> >
>> >> >> >> >> >> >> -----Original Message-----
>> >> >> >> >> >> >> From: zeromq-dev-bounces at lists.zeromq.org [16]
>> >> >> >> [mailto:zeromq-dev- [17]
>> >> >> >> >> >> >> bounces at lists.zeromq.org [18]] On Behalf Of Tom
>> >> Quarendon
>> >> >> >> >> >> >> Sent: Monday, September 15, 2014 11:42 AM
>> >> >> >> >> >> >> To: ZeroMQ development list
>> >> >> >> >> >> >> Subject: Re: [zeromq-dev] ZMQ appends weird
>> >> characters
>> >> >> to
>> >> >> >> >> message
>> >> >> >> >> >> >>
>> >> >> >> >> >> >> > You have two choices:
>> >> >> >> >> >> >> > 1. Send the '' as part of the message (and set
>> >> >> length
>> >> >> >> to
>> >> >> >> >> one
>> >> >> >> >> >> >> more byte).
>> >> >> >> >> >> >> > 2. Append a '' after receiving the message.
>> >> >> >> >> >> >>
>> >> >> >> >> >> >> Uh, why?
>> >> >> >> >> >> >> string(static_cast(reply.data()),reply.size());
>> >> >> >> >> >> >> doesn't assume the string is null terminated. It
>> >> >> constructs
>> >> >> >> >> >> string
>> >> >> >> >> >> >> from pointer and length. Isn't adding a in a null
>> >> just
>> >> >> >> going
>> >> >> >> >> mask
>> >> >> >> >> >> the
>> >> >> >> >> >> >> real issue and make it look like the std::string
>> >> only
>> >> >> >> >> contained
>> >> >> >> >> >> >> "login" when really it still contained the extra
>> >> stuff
>> >> >> as
>> >> >> >> >> well.
>> >> >> >> >> >> >> David, Do you know what reply.size() actually
>> >> contains?
>> >> >> >> Have
>> >> >> >> >> you
>> >> >> >> >> >> >> tried printing that out and comparing it to what you
>> >> >> >> expect?
>> >> >> >> >> >> >>
>> >> >> >> >> >> >> _______________________________________________
>> >> >> >> >> >> >> zeromq-dev mailing list
>> >> >> >> >> >> >> zeromq-dev at lists.zeromq.org [19]
>> >> >> >> >> >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> >> [20]
>> >> >> >> >> >> >
>> >> >> >> >> >> >
>> >> >> >> >> >> > -----------------------------------------
>> >> >> >> >> >> > Declaración de confidencialidad: Este Mensaje esta
>> >> >> destinado
>> >> >> >> >> para
>> >> >> >> >> >> el
>> >> >> >> >> >> > uso de la o las personas o entidades a quien ha sido
>> >> >> >> dirigido y
>> >> >> >> >> >> puede
>> >> >> >> >> >> > contener información reservada y confidencial que no
>> >> >> puede
>> >> >> >> ser
>> >> >> >> >> >> > divulgada, difundida, ni aprovechada en forma alguna.
>> >> El
>> >> >> uso
>> >> >> >> no
>> >> >> >> >> >> > autorizado de la información contenida en este
>> >> correo
>> >> >> podrá
>> >> >> >> ser
>> >> >> >> >> >> > sancionado de conformidad con la ley chilena.
>> >> >> >> >> >> > Si usted ha recibido este correo electrónico por
>> >> error,
>> >> >> le
>> >> >> >> >> pedimos
>> >> >> >> >> >> > eliminarlo junto con los archivos adjuntos y avisar
>> >> >> >> >> inmediatamente
>> >> >> >> >> >> al
>> >> >> >> >> >> > remitente, respondiendo este mensaje.
>> >> >> >> >> >> >
>> >> >> >> >> >> > "Before printing this e-mail think if is really
>> >> >> necesary".
>> >> >> >> >> >> > Disclosure: This Message is to be used by the
>> >> individual,
>> >> >> >> >> >> individuals
>> >> >> >> >> >> > or entities that it is addressed to and may include
>> >> >> private
>> >> >> >> and
>> >> >> >> >> >> > confidential information that may not be disclosed,
>> >> made
>> >> >> >> public
>> >> >> >> >> >> nor
>> >> >> >> >> >> > used in any way at all. Unauthorized use of the
>> >> >> information
>> >> >> >> in
>> >> >> >> >> >> this
>> >> >> >> >> >> > electronic mail message may be subject to the
>> >> penalties
>> >> >> set
>> >> >> >> >> forth
>> >> >> >> >> >> by
>> >> >> >> >> >> > Chilean law.
>> >> >> >> >> >> > If you have received this electronic mail message in
>> >> >> error,
>> >> >> >> we
>> >> >> >> >> ask
>> >> >> >> >> >> you
>> >> >> >> >> >> > to destroy the message and its attached file(s) and
>> >> to
>> >> >> >> >> immediately
>> >> >> >> >> >> > notify the sender by answering this message.
>> >> >> >> >> >> > _______________________________________________
>> >> >> >> >> >> > zeromq-dev mailing list
>> >> >> >> >> >> > zeromq-dev at lists.zeromq.org [21]
>> >> >> >> >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> >> [22]
>> >> >> >> >> >>
>> >> >> >> >> >> _______________________________________________
>> >> >> >> >> >> zeromq-dev mailing list
>> >> >> >> >> >> zeromq-dev at lists.zeromq.org [23]
>> >> >> >> >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> >> [24]
>> >> >> >> >> >
>> >> >> >> >> > -----------------------------------------
>> >> >> >> >> > Declaración de confidencialidad: Este Mensaje esta
>> >> destinado
>> >> >> >> para
>> >> >> >> >> el
>> >> >> >> >> > uso de la o las personas o entidades a quien ha sido
>> >> >> dirigido y
>> >> >> >> >> puede
>> >> >> >> >> > contener información reservada y confidencial que no
>> >> puede
>> >> >> ser
>> >> >> >> >> > divulgada, difundida, ni aprovechada en forma alguna. El
>> >> uso
>> >> >> no
>> >> >> >> >> > autorizado de la información contenida en este correo
>> >> podrá
>> >> >> ser
>> >> >> >> >> > sancionado de conformidad con la ley chilena.
>> >> >> >> >> > Si usted ha recibido este correo electrónico por error,
>> >> le
>> >> >> >> pedimos
>> >> >> >> >> > eliminarlo junto con los archivos adjuntos y avisar
>> >> >> >> inmediatamente
>> >> >> >> >> al
>> >> >> >> >> > remitente, respondiendo este mensaje.
>> >> >> >> >> >
>> >> >> >> >> > "Before printing this e-mail think if is really
>> >> necesary".
>> >> >> >> >> > Disclosure: This Message is to be used by the
>> >> individual,
>> >> >> >> >> individuals
>> >> >> >> >> > or entities that it is addressed to and may include
>> >> private
>> >> >> and
>> >> >> >> >> > confidential information that may not be disclosed, made
>> >> >> public
>> >> >> >> >> nor
>> >> >> >> >> > used in any way at all. Unauthorized use of the
>> >> information
>> >> >> in
>> >> >> >> >> this
>> >> >> >> >> > electronic mail message may be subject to the penalties
>> >> set
>> >> >> >> forth
>> >> >> >> >> by
>> >> >> >> >> > Chilean law.
>> >> >> >> >> > If you have received this electronic mail message in
>> >> error,
>> >> >> we
>> >> >> >> ask
>> >> >> >> >> you
>> >> >> >> >> > to destroy the message and its attached file(s) and to
>> >> >> >> immediately
>> >> >> >> >> > notify the sender by answering this message.
>> >> >> >> >> > _______________________________________________
>> >> >> >> >> > zeromq-dev mailing list
>> >> >> >> >> > zeromq-dev at lists.zeromq.org [25]
>> >> >> >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev [26]
>> >> >> >> >>
>> >> >> >> >> _______________________________________________
>> >> >> >> >> zeromq-dev mailing list
>> >> >> >> >> zeromq-dev at lists.zeromq.org [27]
>> >> >> >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev [28]
>> >> >> >> > _______________________________________________
>> >> >> >> > zeromq-dev mailing list
>> >> >> >> > zeromq-dev at lists.zeromq.org [29]
>> >> >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev [30]
>> >> >> >>
>> >> >> >> _______________________________________________
>> >> >> >> zeromq-dev mailing list
>> >> >> >> zeromq-dev at lists.zeromq.org [31]
>> >> >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev [32]
>> >> >> >
>> >> >> > -----------------------------------------
>> >> >> > Declaración de confidencialidad: Este Mensaje esta destinado
>> >> para
>> >> >> el
>> >> >> > uso de la o las personas o entidades a quien ha sido dirigido
>> >> y
>> >> >> puede
>> >> >> > contener información reservada y confidencial que no puede
>> >> ser
>> >> >> > divulgada, difundida, ni aprovechada en forma alguna. El uso
>> >> no
>> >> >> > autorizado de la información contenida en este correo podrá
>> >> ser
>> >> >> > sancionado de conformidad con la ley chilena.
>> >> >> > Si usted ha recibido este correo electrónico por error, le
>> >> pedimos
>> >> >> > eliminarlo junto con los archivos adjuntos y avisar
>> >> inmediatamente
>> >> >> al
>> >> >> > remitente, respondiendo este mensaje.
>> >> >> >
>> >> >> > "Before printing this e-mail think if is really necesary".
>> >> >> > Disclosure: This Message is to be used by the individual,
>> >> >> individuals
>> >> >> > or entities that it is addressed to and may include private
>> >> and
>> >> >> > confidential information that may not be disclosed, made
>> >> public
>> >> >> nor
>> >> >> > used in any way at all. Unauthorized use of the information in
>> >> >> this
>> >> >> > electronic mail message may be subject to the penalties set
>> >> forth
>> >> >> by
>> >> >> > Chilean law.
>> >> >> > If you have received this electronic mail message in error, we
>> >> ask
>> >> >> you
>> >> >> > to destroy the message and its attached file(s) and to
>> >> immediately
>> >> >> > notify the sender by answering this message.
>> >> >> > _______________________________________________
>> >> >> > zeromq-dev mailing list
>> >> >> > zeromq-dev at lists.zeromq.org [33]
>> >> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev [34]
>> >> >>
>> >> >> _______________________________________________
>> >> >> zeromq-dev mailing list
>> >> >> zeromq-dev at lists.zeromq.org [35]
>> >> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev [36]
>> >> >
>> >> > -----------------------------------------
>> >> > Declaración de confidencialidad: Este Mensaje esta destinado
>> >> para
>> >> > el uso de la o las personas o entidades a quien ha sido dirigido
>> >> y
>> >> > puede contener información reservada y confidencial que no puede
>> >> > ser divulgada, difundida, ni aprovechada en forma alguna. El uso
>> >> no
>> >> > autorizado de la información contenida en este correo podrá ser
>> >> > sancionado de conformidad con la ley chilena.
>> >> > Si usted ha recibido este correo electrónico por error, le
>> >> pedimos
>> >> > eliminarlo junto con los archivos adjuntos y avisar
>> >> inmediatamente
>> >> > al remitente, respondiendo este mensaje.
>> >> >
>> >> > "Before printing this e-mail think if is really necesary".
>> >> > Disclosure: This Message is to be used by the individual,
>> >> > individuals or entities that it is addressed to and may include
>> >> > private and confidential information that may not be disclosed,
>> >> > made public nor used in any way at all. Unauthorized use of the
>> >> > information in this electronic mail message may be subject to the
>> >> > penalties set forth by Chilean law.
>> >> > If you have received this electronic mail message in error, we
>> >> ask
>> >> > you to destroy the message and its attached file(s) and to
>> >> > immediately notify the sender by answering this message.
>> >> > _______________________________________________
>> >> > zeromq-dev mailing list
>> >> > zeromq-dev at lists.zeromq.org [37]
>> >> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev [38]
>> >>
>> >> _______________________________________________
>> >> zeromq-dev mailing list
>> >> zeromq-dev at lists.zeromq.org [39]
>> >> http://lists.zeromq.org/mailman/listinfo/zeromq-dev [40]
>> >
>> >
>> >
>> > Links:
>> > ------
>> > [1] http://pastebin.com/AgUuDqqK
>> > [2] mailto:zeromq-dev-bounces at lists.zeromq.org
>> > [3] mailto:zeromq-dev-
>> > [4] mailto:bounces at lists.zeromq.org
>> > [5] mailto:zeromq-dev-bounces at lists.zeromq.org
>> > [6] mailto:zeromq-dev-
>> > [7] mailto:bounces at lists.zeromq.org
>> > [8] mailto:zeromq-dev-bounces at lists.zeromq.org
>> > [9] mailto:zeromq-dev-
>> > [10] mailto:bounces at lists.zeromq.org
>> > [11] http://example.org/path/to/jsp?lang=en_US?session=
>> > [12] mailto:zeromq-dev-bounces at lists.zeromq.org
>> > [13] mailto:zeromq-dev-
>> > [14] mailto:bounces at lists.zeromq.org
>> > [15] mailto:zeromq-dev at lists.zeromq.org
>> > [16] mailto:zeromq-dev-bounces at lists.zeromq.org
>> > [17] mailto:zeromq-dev-
>> > [18] mailto:bounces at lists.zeromq.org
>> > [19] mailto:zeromq-dev at lists.zeromq.org
>> > [20] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [21] mailto:zeromq-dev at lists.zeromq.org
>> > [22] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [23] mailto:zeromq-dev at lists.zeromq.org
>> > [24] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [25] mailto:zeromq-dev at lists.zeromq.org
>> > [26] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [27] mailto:zeromq-dev at lists.zeromq.org
>> > [28] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [29] mailto:zeromq-dev at lists.zeromq.org
>> > [30] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [31] mailto:zeromq-dev at lists.zeromq.org
>> > [32] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [33] mailto:zeromq-dev at lists.zeromq.org
>> > [34] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [35] mailto:zeromq-dev at lists.zeromq.org
>> > [36] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [37] mailto:zeromq-dev at lists.zeromq.org
>> > [38] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [39] mailto:zeromq-dev at lists.zeromq.org
>> > [40] http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>> > [41] mailto:mail at davidkaya.sk
>>
>> _______________________________________________
>> zeromq-dev mailing list
>> zeromq-dev at lists.zeromq.org
>> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>>
>
>
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