Memory leaking..

[Jack Klein]

Re: Memory leaking..

On Thu, 15 Nov 2007 01:58:44 -0800 (PST), "dSpam@arcor.de "
<dSpam@arcor.de wrote in comp.lang.c:

On 15 Nov., 08:20, Ian Collins <ian-n...@hotmail.co mwrote:

gNash wrote:

what it mean?

I've no idea, never having used valgrind. All I can say is it is wrong.

>
If you've no idea what something means, you cannot know that it is
wrong. (But of course you can say it regardless.)

Yes, he can. As far as the C language is concerned, and that's the
only thing that counts here, free() was properly called on a pointer
returned from malloc(). Since the free() function cannot fail if
called correctly, as it is in this case, the memory was freed.

Neither Ian nor I have to know much about valgrind, the Magna Carta,
or a Comcast commercial featuring the Slowskys, to state that if they
say this memory was not freed, the are wrong.

The memory was freed in the only context that matters in this group.

--
Jack Klein
Home: http://JK-Technology.Com
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[Pietro Cerutti]

Re: Memory leaking..

Richard Heathfield wrote:

[5] - if logic were any guide, it would make sense for memcpy to perform
the copy faster than strcpy.

Which logic would say so?


--
Pietro Cerutti

PGP Public Key:

http://gahr.ch/pgp

[Richard Heathfield]

Re: Memory leaking..

Pietro Cerutti <gahr_AT_gahr_D OT_ch_DO_NOT_SP AMsaid:

Richard Heathfield wrote:

>[5] - if logic were any guide, it would make sense for memcpy to perform
>the copy faster than strcpy.

>
Which logic would say so?

With memcpy, you know the length in advance, so you can perform
optimisations such as copying four, eight, or even more bytes at a time,
whereas with strcpy that's a lot harder because you have to check for the
null terminator all the time. So you'd *expect* memcpy to be faster. In
practice, it need not be, and sometimes isn't.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Philip Potter]

Re: Memory leaking..

Jack Klein wrote:

On Thu, 15 Nov 2007 01:58:44 -0800 (PST), "dSpam@arcor.de "
<dSpam@arcor.de wrote in comp.lang.c:
>

>On 15 Nov., 08:20, Ian Collins <ian-n...@hotmail.co mwrote:

>>gNash wrote:
>>>what it mean?
>>I've no idea, never having used valgrind. All I can say is it is wrong.

>If you've no idea what something means, you cannot know that it is
>wrong. (But of course you can say it regardless.)

>
Yes, he can. As far as the C language is concerned, and that's the
only thing that counts here, free() was properly called on a pointer
returned from malloc(). Since the free() function cannot fail if
called correctly, as it is in this case, the memory was freed.
>
Neither Ian nor I have to know much about valgrind, the Magna Carta,
or a Comcast commercial featuring the Slowskys, to state that if they
say this memory was not freed, the are wrong.
>
The memory was freed in the only context that matters in this group.

But it didn't say it wasn't freed, it said it was "still reachable".
That means "No memory leak" in valgrind terms.

--
Philip Potter pgp <atdoc.ic.ac. uk

[dSpam@arcor.de]

Re: Memory leaking..

On 16 Nov., 04:44, Jack Klein <jackkl...@spam cop.netwrote:

On Thu, 15 Nov 2007 01:58:44 -0800 (PST), "dS...@arcor.de "
<dS...@arcor.de wrote in comp.lang.c:

If you've no idea what something means, you cannot know that it is
wrong. (But of course you can say it regardless.)

>
Yes, he can. As far as the C language is concerned, ...

May I suggest that you think this over? I maintain that my statement
above is true in every context, be it the C language or anything else.

[Richard Heathfield]

Re: Memory leaking..

Jack Klein said:

On Thu, 15 Nov 2007 01:58:44 -0800 (PST), "dSpam@arcor.de "
<dSpam@arcor.de wrote in comp.lang.c:
>

>On 15 Nov., 08:20, Ian Collins <ian-n...@hotmail.co mwrote:

gNash wrote:
what it mean?
>
I've no idea, never having used valgrind. All I can say is it is
wrong.

>>
>If you've no idea what something means, you cannot know that it is
>wrong. (But of course you can say it regardless.)

>
Yes, he can.

No, he can't.

As far as the C language is concerned, and that's the
only thing that counts here, free() was properly called on a pointer
returned from malloc(). Since the free() function cannot fail if
called correctly, as it is in this case, the memory was freed.

Indeed.

Neither Ian nor I have to know much about valgrind, the Magna Carta,
or a Comcast commercial featuring the Slowskys, to state that if they
say this memory was not freed, the are wrong.

So what you're really saying is that, if you *do* know what something
means, you can know that it is wrong.

The memory was freed in the only context that matters in this group.

Nobody disputes that (AFAIK!).

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

[Chris Dollin]

Re: Memory leaking..

dSpam@arcor.de wrote:

On 16 Nov., 04:44, Jack Klein <jackkl...@spam cop.netwrote:

>On Thu, 15 Nov 2007 01:58:44 -0800 (PST), "dS...@arcor.de "
><dS...@arcor.d ewrote in comp.lang.c:

If you've no idea what something means, you cannot know that it is
wrong. (But of course you can say it regardless.)

>>
>Yes, he can. As far as the C language is concerned, ...

>
May I suggest that you think this over? I maintain that my statement
above is true in every context, be it the C language or anything else.

You can know that what something /says/ is false, but have independent
evidence that the said thing is [taken to be] true. From this you may
conclude that it doesn't mean what it says, and so you've no idea what
it means. But you do know that what it says is wrong.

--
Chris "the application to standards is obvious" Dollin

Hewlett-Packard Limited Cain Road, Bracknell, registered no:
registered office: Berks RG12 1HN 690597 England

[Tor Rustad]

Re: Memory leaking..

Richard Heathfield wrote:

Jack Klein said:

[...]

>The memory was freed in the only context that matters in this group.

>
Nobody disputes that (AFAIK!).

Why, isn't static storage duration of string literals relevant?

Methinks valgrind reported this:

char *str="Five pineapples";

--
Tor <bwzcab@wvtqvm. vw | tr i-za-h a-z>

[J. J. Farrell]

Re: Memory leaking..

Jack Klein wrote:

On Thu, 15 Nov 2007 01:58:44 -0800 (PST), "dSpam@arcor.de "
<dSpam@arcor.de wrote in comp.lang.c:
>

>On 15 Nov., 08:20, Ian Collins <ian-n...@hotmail.co mwrote:

>>gNash wrote:
>>>what it mean?
>>I've no idea, never having used valgrind. All I can say is it is wrong.

>If you've no idea what something means, you cannot know that it is
>wrong. (But of course you can say it regardless.)

>
Yes, he can. As far as the C language is concerned, and that's the
only thing that counts here, free() was properly called on a pointer
returned from malloc(). Since the free() function cannot fail if
called correctly, as it is in this case, the memory was freed.
>
Neither Ian nor I have to know much about valgrind, the Magna Carta,
or a Comcast commercial featuring the Slowskys, to state that if they
say this memory was not freed, the are wrong.

Something of a straw man, Jack. Whoever said that the memory was not
freed? Valgrind reportedly said "16 byts (sic) in 1 block still
reachable". Does that have anything to do with memory being freed? I
don't know. I have no idea what it means. I don't know whether or not it
is wrong, since I don't know what it is trying to say. Ian appears to be
in much the same position as me, since when asked what it means he said
"I've no idea, never having used valgrind". However, he went on to say
that the message was wrong. Since he does not know what the message
means he cannot know it is wrong, and is wrong to say that it is wrong.
For all that you, I, or Ian know, it might be Valgrind's obscure way of
saying "all memory allocated by malloc() has been correctly freed".

The memory was freed in the only context that matters in this group.

The OP's question may be off-topic, but that doesn't impinge on whether
or not the message was wrong; it impinges on our ability to say whether
or not the message was wrong.