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Re: passing uninitialised data

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On 09/14/2012 03:03 PM, Angel wrote:
> On 2012-09-14, Mark <mark_cruzNOTFORSPAM@hotmail.com> wrote:
>> Hello,
>>
>> I have quite a generic question. Suppose we work with fwrite(), or sendto() 
>> (not C standard function, but I'll assume everyone knows it) or any other 
>> API that takes a pointer to a buffer to transmit. When such a buffer is 
>> unititialised, does it in some ways impose undefined behaviour?
> 
> Passing a pointer to a function that expects such is well defined, no
> matter if the object the pointer points to is initialized or not.

There's a reason why valgrind is giving him warning messages about this.
It's quite trivial to write code that has undefined behavior when passed
a pointer to an uninitialized buffer. What precisely is encompassed by
the phrase "that expects such"?

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passing uninitialised data "Mark" <mark_cruzNOTFORSPAM@hotmail.com> - 2012-09-14 11:09 -0400
  Re: passing uninitialised data Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-09-14 11:45 -0400
  Re: passing uninitialised data James Kuyper <jameskuyper@verizon.net> - 2012-09-14 11:48 -0400
    Re: passing uninitialised data Barry Schwarz <schwarzb@dqel.com> - 2012-09-14 10:34 -0700
      Re: passing uninitialised data James Kuyper <jameskuyper@verizon.net> - 2012-09-14 14:34 -0400
        Re: passing uninitialised data Barry Schwarz <schwarzb@dqel.com> - 2012-09-14 15:26 -0700
          Re: passing uninitialised data James Kuyper <jameskuyper@verizon.net> - 2012-09-17 12:18 -0400
      Re: passing uninitialised data Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-17 11:52 -0800
        Re: passing uninitialised data pete <pfiland@mindspring.com> - 2012-12-17 16:21 -0500
          Re: passing uninitialised data Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-20 10:23 -0800
            Re: passing uninitialised data pete <pfiland@mindspring.com> - 2012-12-20 21:17 -0500
              Re: passing uninitialised data Tim Rentsch <txr@alumni.caltech.edu> - 2012-12-21 09:20 -0800
                Re: passing uninitialised data pete <pfiland@mindspring.com> - 2012-12-21 14:52 -0500
                Re: passing uninitialised data glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2012-12-21 21:19 +0000
        Re: passing uninitialised data Shao Miller <sha0.miller@gmail.com> - 2012-12-17 19:45 -0500
  Re: passing uninitialised data Angel <angel+news@spamcop.net> - 2012-09-14 19:03 +0000
    Re: passing uninitialised data James Kuyper <jameskuyper@verizon.net> - 2012-09-14 15:15 -0400
      Re: passing uninitialised data Angel <angel+news@spamcop.net> - 2012-09-14 20:26 +0000
        Re: passing uninitialised data James Kuyper <jameskuyper@verizon.net> - 2012-09-14 16:45 -0400
      Re: passing uninitialised data Kaz Kylheku <kaz@kylheku.com> - 2012-09-14 21:19 +0000

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