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Open letter to Ian Collins

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  Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 00:22 +0200
    Re: Open letter to Ian Collins Ike Naar <ike@sverige.freeshell.org> - 2012-05-26 22:36 +0000
      Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 01:13 +0200
        Re: Open letter to Ian Collins Barry Schwarz <schwarzb@dqel.com> - 2012-05-26 16:53 -0700
      Re: Open letter to Ian Collins Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-05-26 16:41 -0700
        Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-26 22:43 -0400
    Re: Open letter to Ian Collins Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-05-26 15:41 -0700
      Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 01:14 +0200
    Re: Open letter to Ian Collins MelissA <melis@a.com> - 2012-05-27 00:52 +0200
    Re: Open letter to Ian Collins Stephen Sprunk <stephen@sprunk.org> - 2012-05-26 20:40 -0500
      Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 09:32 +0200
        Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-27 07:18 -0400
    Re: Open letter to Ian Collins Ian Collins <ian-news@hotmail.com> - 2012-05-27 14:24 +1200
      Re: Open letter to Ian Collins "BartC" <bc@freeuk.com> - 2012-05-27 10:36 +0100
        Re: Open letter to Ian Collins Ian Collins <ian-news@hotmail.com> - 2012-05-27 22:33 +1200
          Re: Open letter to Ian Collins "BartC" <bc@freeuk.com> - 2012-05-27 12:25 +0100
            Re: Open letter to Ian Collins Ian Collins <ian-news@hotmail.com> - 2012-05-28 07:17 +1200
        Re: Open letter to Ian Collins Ike Naar <ike@sverige.freeshell.org> - 2012-05-27 13:03 +0000
    Re: Open letter to Ian Collins Ian Collins <ian-news@hotmail.com> - 2012-05-27 15:16 +1200
      Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 09:30 +0200
        Re: Open letter to Ian Collins Ian Collins <ian-news@hotmail.com> - 2012-05-27 20:56 +1200
          Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 11:12 +0200
            Re: Open letter to Ian Collins Ian Collins <ian-news@hotmail.com> - 2012-05-27 21:22 +1200
              Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-27 07:15 -0400
              Re: Open letter to Ian Collins Keith Thompson <kst-u@mib.org> - 2012-05-27 07:49 -0700
                Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-27 13:55 -0400
                  Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 22:24 +0200
                    Re: Open letter to Ian Collins "BartC" <bc@freeuk.com> - 2012-05-27 22:09 +0100
                      Re: Open letter to Ian Collins Keith Thompson <kst-u@mib.org> - 2012-05-27 14:33 -0700
                        Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-27 17:49 -0400
                    Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-27 17:31 -0400
                      Re: Open letter to Ian Collins Philip Lantz <prl@canterey.us> - 2012-05-28 01:38 -0700
                        Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-05-28 08:18 -0400
          Re: Open letter to Ian Collins "BartC" <bc@freeuk.com> - 2012-05-27 15:46 +0100
          Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-06-13 21:25 -0400
            Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-06-13 21:52 -0400
            Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-06-14 04:00 +0200
              Re: Open letter to Ian Collins pete <pfiland@mindspring.com> - 2012-06-14 00:04 -0400
    Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-27 09:42 +0200
    Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-28 12:39 +0200
      Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-28 21:44 +0200
        Re: Open letter to Ian Collins jacob navia <jacob@spamsink.net> - 2012-05-29 09:46 +0200
          Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-29 10:06 +0200
            Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-29 10:37 +0200
              Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-29 10:58 +0200
                Re: Open letter to Ian Collins "Joachim Schmitz" <nospam.jojo@schmitz-digital.de> - 2012-05-29 11:34 +0200
                Re: Open letter to Ian Collins Malcolm McLean <malcolm.mclean5@btinternet.com> - 2012-05-29 03:02 -0700
        Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-29 09:59 +0200
        Re: Open letter to Ian Collins "io_x" <a@b.c.invalid> - 2012-05-29 20:09 +0200
    Re: Open letter to Ian Collins "Sarah Wren" <swreb@ameritech.net> - 2012-05-29 01:40 -0600

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#21381 — Open letter to Ian Collins

Hi Ian

In the c++ newsgroup you asked me for an example of the ccl performance
It was something with building a huge list, then sorting it, if I 
remember correctly...

I have built this example code:

#include <stdlib.h>
#include "containers.h"
#define N 10000000
int main(void)
{
         List *L1;
         size_t i,d;
         long long sum=0,newSum=0;
         Iterator *it;
         int *pint;

         L1 = iList.Create(sizeof(int));
         iList.UseHeap(L1,NULL);
         for (i=0; i<N;i++) {
                 d = rand();
                 sum += d;
                 iList.Add(L1,&d);
         }
         iList.Sort(L1);
         it = iList.NewIterator(L1);
         for (pint = it->GetFirst(it); pint; pint = it->GetNext(it)) {
                 newSum += *pint;
         }
         if (sum != newSum)
                 printf("Failed\n");
         else    printf("Sum = %lld\n",sum);
         iList.Finalize(L1);
}

This creates a list, then fills it with 10 million random integers,
then sorts it and verifies that all the data is still there by
accessing all elements of the list with an iterator.

Can you please send me an equivalent C++program?

Thanks

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#21382

On 2012-05-26, jacob navia <jacob@spamsink.net> wrote:
> Hi Ian
>
> In the c++ newsgroup you asked me for an example of the ccl performance
> It was something with building a huge list, then sorting it, if I 
> remember correctly...
>
> I have built this example code:
>
> #include <stdlib.h>
> #include "containers.h"
> #define N 10000000
> int main(void)
> {
>          List *L1;
>          size_t i,d;
>          long long sum=0,newSum=0;
>          Iterator *it;
>          int *pint;
>
>          L1 = iList.Create(sizeof(int));
>          iList.UseHeap(L1,NULL);
>          for (i=0; i<N;i++) {
>                  d = rand();
>                  sum += d;
>                  iList.Add(L1,&d);

This seems dangerous. iList.Add expects a pointer to an
int for the second argument, and it receives a pointer to
a size_t. What if int and size_t have different sizes?

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#21385

Le 27/05/12 00:36, Ike Naar a écrit :
> This seems dangerous. iList.Add expects a pointer to an
> int for the second argument, and it receives a pointer to
> a size_t. What if int and size_t have different sizes?

Well, the list software will read the lower sizeof(int) bytes, that's
all.

The other way around would be dangerous: passing a pointer to int to a
size_t;

But strictly speaking you are right of course. Will change that.

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#21388

On Sun, 27 May 2012 01:13:37 +0200, jacob navia <jacob@spamsink.net>
wrote:

>Le 27/05/12 00:36, Ike Naar a écrit :
>> This seems dangerous. iList.Add expects a pointer to an
>> int for the second argument, and it receives a pointer to
>> a size_t. What if int and size_t have different sizes?
>
>Well, the list software will read the lower sizeof(int) bytes, that's
>all.

And on a big-endian machine this will produce the correct value?

Not to mention the mandatory diagnostic during compilation.

>
>The other way around would be dangerous: passing a pointer to int to a
>size_t;
>
>But strictly speaking you are right of course. Will change that.

Even casually speaking.

-- 
Remove del for email

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#21387

בתאריך יום שבת, 26 במאי 2012 23:36:29 UTC+1, מאת Ike Naar:
> 
> This seems dangerous. iList.Add expects a pointer to an
> int for the second argument, and it receives a pointer to
> a size_t. What if int and size_t have different sizes?
>
Yes, size_t is a menace. I've been saying that for a while. The problem is that programmers are unwilling to use it consistently. If you want an integer, you type int. 

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#21392

Malcolm McLean wrote:
> 
> בתאריך יום שבת, 26 במאי 2012 23:36:29 UTC+1, מאת Ike Naar:
> >
> > This seems dangerous. iList.Add expects a pointer to an
> > int for the second argument, and it receives a pointer to
> > a size_t. What if int and size_t have different sizes?
> >
> Yes, size_t is a menace. I've been saying that for a while.
> The problem is that programmers are unwilling to use it consistently.
> If you want an integer, you type int.

In this case, I don't think that (size_t)
was the best choice for either (i) or (d).

(i) was counting nodes in a list
and the standard definition of what (size_t) is supposed to be,
isn't related to how many nodes can be in a list.
I think I would have used the largest unsigned integer type for (i).

(d) was assigned the return value of rand(),
so (int) is the type that would first occur to me to use for (d).

Unsigned integer types would have been the first thing
to occur to me to use for the checksums.

And even though nobody wants to see it,
this is how I would have written a program like that in C:

http://www.mindspring.com/~pfilandr/C/lists_and_files/list_lib.h 
http://www.mindspring.com/~pfilandr/C/lists_and_files/list_lib.c 
http://www.mindspring.com/~pfilandr/C/lists_and_files/list_type.h 



/* BEGIN new.c */

#include "list_lib.h"

#include <stdio.h>
#include <stdlib.h>

#define N 1000000

#define str(s)          # s
#define xstr(s)         str(s)

int int_comp(const void *a, const void *b);

int 
main(void)
{
    int d, *d_ptr;
    long unsigned i;
    unsigned old_checksum = 0;
    unsigned new_checksum = 0;
    list_type *head = NULL;
    list_type *tail = NULL;
    

    puts("/* BEGIN output new.c */\n\nN is " xstr(N) "\n");
    for (i = 0; i != N; ++i) {
        d = rand();
        old_checksum += d;
        tail = list_append(&head, tail, &d, sizeof d);
        if (tail == NULL) {
            puts("tail == NULL");
            printf("list only contains %lu nodes,\n\n", i);
            break;
        }
    }
    tail = head = list_sort(head, int_comp);    
    while (tail != NULL) {
        d_ptr = tail -> data;
        d = *d_ptr;
        new_checksum += d;
        tail = tail -> next;
        if (tail != NULL && int_comp(d_ptr, tail -> data) > 0) {
            puts("list is out of order\n");
            break;            
        }
    }
    list_free(head, free);
    head = tail = NULL;
    printf("old_checksum is %lu.\n", old_checksum);
    printf("new_checksum is %lu.\n", new_checksum);
    puts("\n/* END output new.c */");
    return 0;
}

int 
int_comp(const void *a, const void *b)
{
    const int *const aa = a;
    const int *const bb = b;

    return *bb > *aa ? -1 : *bb != *aa;
}

/* END new.c */


-- 
pete

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#21383

בתאריך יום שבת, 26 במאי 2012 23:22:01 UTC+1, מאת jacob navia:
>          iList.Sort(L1);
> Can you please send me an equivalent C++program?
> 
You very rarely want to sort a list of integers or other atomic type. Almost always you want to sort records based on a field, or on two fields, e.g. surname followed by intials, or you want to do somethign funny, like sorting strings alphabetically but putting embedded numbers in numeric order so that fred_99 comes before fred_100.
 

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#21386

Le 27/05/12 00:41, Malcolm McLean a écrit :
> בתאריך יום שבת, 26 במאי 2012 23:22:01 UTC+1, מאת jacob navia:
>>           iList.Sort(L1);
>> Can you please send me an equivalent C++program?
>>
> You very rarely want to sort a list of integers or other atomic type.

Almost always you want to sort records based on a field, or on two fields,

e.g. surname followed by intials, or you want to do somethign funny,

like sorting strings alphabetically but putting embedded numbers in

numeric order so that fred_99 comes before fred_100.
>
>

I know, it is just for comparing performance of ccl vs stl

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#21384

On Sun, 27 May 2012 00:22:01 +0200
jacob navia <jacob@spamsink.net> wrote:

> Hi Ian
> 
> In the c++ newsgroup you asked me for an example of the ccl
> performance It was something with building a huge list, then sorting
> it, if I remember correctly...
> 
> I have built this example code:
> 
> #include <stdlib.h>
> #include "containers.h"
> #define N 10000000
> int main(void)
> {
>          List *L1;
>          size_t i,d;
>          long long sum=0,newSum=0;
>          Iterator *it;
>          int *pint;
> 
>          L1 = iList.Create(sizeof(int));
>          iList.UseHeap(L1,NULL);
>          for (i=0; i<N;i++) {
>                  d = rand();
>                  sum += d;
>                  iList.Add(L1,&d);
>          }
>          iList.Sort(L1);
>          it = iList.NewIterator(L1);
>          for (pint = it->GetFirst(it); pint; pint = it->GetNext(it)) {
>                  newSum += *pint;
>          }
>          if (sum != newSum)
>                  printf("Failed\n");
>          else    printf("Sum = %lld\n",sum);
>          iList.Finalize(L1);
> }
> 
> This creates a list, then fills it with 10 million random integers,
> then sorts it and verifies that all the data is still there by
> accessing all elements of the list with an iterator.
> 
> Can you please send me an equivalent C++program?
> 
> Thanks

Well, I have tested list sorting and traversing and quick sort
by value (doesn't change nodes order) is much faster than
standard stl list sort (which changes nodes order).
Also after sort that doesn't change nodes order, traversing
is much faster then after sort that does change nodes order.
That is of course if initial list nodes are consecutive.
Doesn't matter how much cache cpu has 512kb is enough
to show significant difference.

Greetings!

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#21390

On 26-May-12 17:22, jacob navia wrote:
> Hi Ian
> 
> In the c++ newsgroup you asked me for an example of the ccl performance
> It was something with building a huge list, then sorting it, if I
> remember correctly...

Then shouldn't you have posted the response to "the c++ newsgroup"
rather than comp.lang.c?

> [a bunch of C++ code]

Off-topic here.

S

-- 
Stephen Sprunk         "God does not play dice."  --Albert Einstein
CCIE #3723         "God is an inveterate gambler, and He throws the
K5SSS        dice at every possible opportunity." --Stephen Hawking

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#21396

Le 27/05/12 03:40, Stephen Sprunk a écrit :
>> [a bunch of C++ code]

Why is it C++?

It compiles with every C compiler you can choose...

Never mind, don't let facts disturb your beliefs.

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#21407

jacob navia wrote:
> 
> Le 27/05/12 03:40, Stephen Sprunk a écrit :
> >> [a bunch of C++ code]
> 
> Why is it C++?

He probably didn't know what "containers.h" was.

> It compiles with every C compiler you can choose...
> 
> Never mind, don't let facts disturb your beliefs.


-- 
pete

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#21391

On 05/27/12 10:22 AM, jacob navia wrote:
> Hi Ian
>
> In the c++ newsgroup you asked me for an example of the ccl performance
> It was something with building a huge list, then sorting it, if I
> remember correctly...
>
> I have built this example code:
>
> #include<stdlib.h>
> #include "containers.h"
> #define N 10000000
> int main(void)
> {
>           List *L1;
>           size_t i,d;
>           long long sum=0,newSum=0;
>           Iterator *it;
>           int *pint;

All good code should have at least one beer reference!

It be a lot easier to see what is what if these were declared on first use.

>           L1 = iList.Create(sizeof(int));
>           iList.UseHeap(L1,NULL);
>           for (i=0; i<N;i++) {
>                   d = rand();
>                   sum += d;
>                   iList.Add(L1,&d);
>           }
>           iList.Sort(L1);
>           it = iList.NewIterator(L1);
>           for (pint = it->GetFirst(it); pint; pint = it->GetNext(it)) {
>                   newSum += *pint;
>           }
>           if (sum != newSum)
>                   printf("Failed\n");
>           else    printf("Sum = %lld\n",sum);
>           iList.Finalize(L1);
> }
>
> This creates a list, then fills it with 10 million random integers,
> then sorts it and verifies that all the data is still there by
> accessing all elements of the list with an iterator.
>
> Can you please send me an equivalent C++program?

I did (with the addition of using one list to initialise another) in the 
c.l.c++ thread you should have posted this in response to.

-- 
Ian Collins

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#21403

"Ian Collins" <ian-news@hotmail.com> wrote in message
news:a2dhipF7faU1@mid.individual.net...
> On 05/27/12 10:22 AM, jacob navia wrote:
>> Hi Ian
>>
>> In the c++ newsgroup you asked me for an example of the ccl performance
>> It was something with building a huge list, then sorting it, if I
>> remember correctly...
>>
>> I have built this example code:
>>
>> #include<stdlib.h>
>> #include "containers.h"
>> #define N 10000000
>> int main(void)
>> {
>>           List *L1;
>>           size_t i,d;
>>           long long sum=0,newSum=0;
>>           Iterator *it;
>>           int *pint;
>
> All good code should have at least one beer reference!
>
> It be a lot easier to see what is what if these were declared on first
> use.

As in, instead of reading a play which starts with a cast of characters,
they should be introduced whenever they first appear?

Suppose you're delving into a random scene, (or have an extract for use
elsewhere), and want to be reminded who a character is, you have to start
ploughing through from page one first until you encounter their first 
mention?

And if you are editing the play, and the character's first appearance is 
edited out, or is moved somewhere where it's no longer the first appearance; 
how much work is it going to be to fix up declarations properly?

Getting back to C, wouldn't macros and enumerations (and file-scope
variables, external references, etc) also all benefit from being declared
where they are first used? (And what sort of mess would that make of any
program...).

Anyway I thought  everyone used smart editors now, where you hover over a
name or something, and it tells you everything about it.

-- 
Bartc

 

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#21405

On 05/27/12 09:36 PM, BartC wrote:
>
>
> "Ian Collins"<ian-news@hotmail.com>  wrote in message
> news:a2dhipF7faU1@mid.individual.net...
>> On 05/27/12 10:22 AM, jacob navia wrote:
>>> Hi Ian
>>>
>>> In the c++ newsgroup you asked me for an example of the ccl performance
>>> It was something with building a huge list, then sorting it, if I
>>> remember correctly...
>>>
>>> I have built this example code:
>>>
>>> #include<stdlib.h>
>>> #include "containers.h"
>>> #define N 10000000
>>> int main(void)
>>> {
>>>            List *L1;
>>>            size_t i,d;
>>>            long long sum=0,newSum=0;
>>>            Iterator *it;
>>>            int *pint;
>>
>> All good code should have at least one beer reference!
>>
>> It be a lot easier to see what is what if these were declared on first
>> use.
>
> As in, instead of reading a play which starts with a cast of characters,
> they should be introduced whenever they first appear?
>
> Suppose you're delving into a random scene, (or have an extract for use
> elsewhere), and want to be reminded who a character is, you have to start
> ploughing through from page one first until you encounter their first
> mention?

A function is more like a limerick than a play.

> And if you are editing the play, and the character's first appearance is
> edited out, or is moved somewhere where it's no longer the first appearance;
> how much work is it going to be to fix up declarations properly?

No a lot.

> Getting back to C, wouldn't macros and enumerations (and file-scope
> variables, external references, etc) also all benefit from being declared
> where they are first used? (And what sort of mess would that make of any
> program...).

I would make them longer, unlike declaring variables when they are 
needed makes them shorter.  Besides, how do you introduce a const other 
that where it is initialised?

> Anyway I thought  everyone used smart editors now, where you hover over a
> name or something, and it tells you everything about it.

Alas, Thunderbird lack that feature.

-- 
Ian Collins

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#21409

"Ian Collins" <ian-news@hotmail.com> wrote in message
news:a2ee73F7faU5@mid.individual.net...
> On 05/27/12 09:36 PM, BartC wrote:
>> "Ian Collins"<ian-news@hotmail.com>  wrote in message

>>> It be a lot easier to see what is what if these were declared on first
>>> use.
>>
>> As in, instead of reading a play which starts with a cast of characters,
>> they should be introduced whenever they first appear?
>>
>> Suppose you're delving into a random scene, (or have an extract for use
>> elsewhere), and want to be reminded who a character is, you have to start
>> ploughing through from page one first until you encounter their first
>> mention?
>
> A function is more like a limerick than a play.

In that case I can't see it being a big imposition if the names were
declared at the top of the function (ie. at the top of the screen if a
function is small). Then it gets the clutter out of the code. And all uses
of the name are identical (instead of one of them needing a declaration).
Although, it will make the function a bit longer..

>> Getting back to C, wouldn't macros and enumerations .... also
>> all benefit from being declared where they are first used?

> I would make them longer, unlike declaring variables when they are needed
> makes them shorter.

That's another thing; uses of i, j and k for loop indices is fairly
standard. They probably will be ints, and the formality of having to declare
them can be kept out of the way instead of making for-loops even longer.
(Alternatively for-loop variables could be implicitly declared.)

> Besides, how do you introduce a const other that where it is initialised?

What do you mean by a const? If it is a name that is to be used in several
places, then it can also benefit from splitting declaration (and 
initialisation) from it's use.

It gets more complicated when declarations in blocks are used (which
apparently have their own name spaces). But I've never used those, and if
functions are small as everyone says they should be, I can't see the need.

(Of course my point of view is from reading code rather than writing it. But
the former should have priority.)

-- 
Bartc 

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#21421

On 05/27/12 11:25 PM, BartC wrote:
> "Ian Collins"<ian-news@hotmail.com>  wrote in message
> news:a2ee73F7faU5@mid.individual.net...
>> On 05/27/12 09:36 PM, BartC wrote:
>
>>> Getting back to C, wouldn't macros and enumerations .... also
>>> all benefit from being declared where they are first used?
>
>> I would make them longer, unlike declaring variables when they are needed
>> makes them shorter.
>
> That's another thing; uses of i, j and k for loop indices is fairly
> standard. They probably will be ints, and the formality of having to declare
> them can be kept out of the way instead of making for-loops even longer.
> (Alternatively for-loop variables could be implicitly declared.)

Declaring loop indexes in the loop makes it clear that's what they are 
and that they won't spill out.

>> Besides, how do you introduce a const other that where it is initialised?
>
> What do you mean by a const? If it is a name that is to be used in several
> places, then it can also benefit from splitting declaration (and
> initialisation) from it's use.

const in t n = some_expression;

-- 
Ian Collins

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#21411

On 2012-05-27, BartC <bc@freeuk.com> wrote:
> Suppose you're delving into a random scene, (or have an extract for use
> elsewhere), and want to be reminded who a character is, you have to start
> ploughing through from page one first until you encounter their first 
> mention?

It depends. 
When a variable is declared on first use, the active scope of the variable
is sometimes reduced to a few lines of code. So, to find the declaration, one
has to plough backward for a few lines. That may take less ploughing than
when the declaration is at the beginning of the function.

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#21393

On 05/27/12 10:22 AM, jacob navia wrote:
> Hi Ian
>
> In the c++ newsgroup you asked me for an example of the ccl performance
> It was something with building a huge list, then sorting it, if I
> remember correctly...
>
> I have built this example code:
>
<snip>

I get a segv when I run the example.  Running in dbx with access 
checking enabled shows:

Write to unallocated (wua):
Attempting to write 1 byte at address 0x8091d88
     which is just past heap block of size 800 bytes at 0x8091a68
This block was allocated from:
         newHeapObject<-NewLink<-Add_nd<-Add<-main
Location of error: heap.c, line 75, newHeapObject()

The offending code appears to be here in heap.c:

      /* The array of block pointers is full. Allocate CHUNK_SIZE blocks 
more */
       siz = (l->BlockCount+CHUNK_SIZE)*sizeof(ListElement *);
       result = l->Allocator->realloc(l->Heap,siz);
       if (result == NULL) {
         return NULL;
       }
       l->MemoryUsed+= siz;
       l->Heap = (char **)result;
       /* Position pointer at the start of the new area */
       result += l->BlockCount*sizeof(ListElement *);
       /* Zero the new pointers */
       memset(result,0,siz);

It looks like you are allocating siz byes, incrementing part (half) way 
through the bock then zeroing the next siz bytes.

-- 
Ian Collins

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#21395

Le 27/05/12 05:16, Ian Collins a écrit :
> On 05/27/12 10:22 AM, jacob navia wrote:
>> Hi Ian
>>
>> In the c++ newsgroup you asked me for an example of the ccl performance
>> It was something with building a huge list, then sorting it, if I
>> remember correctly...
>>
>> I have built this example code:
>>
> <snip>
>
> I get a segv when I run the example. Running in dbx with access checking
> enabled shows:

I corrected that yesterday. When you asked me gthis example I was in the
middle of a reorganization of heap.c. Look at the latest update

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