how to malloc 2G ram? in freebsd, win2k

hi
i try to malloc 2G size mem . so i wirte code like that.
it failt in freebsd 5.3 and win2k

what's bug in my code ? how can i change it ?

thank all :)
benjiam
///////////////////////////////////////////////
#include <iostream>
using namespace std;

#include <cstdlib>
const int len = 2000;
int main()
{
char* p1[len];
static int size = int (1<<20);
cout << size << endl;
for (int i =0 ; i < len ;i++)
{
p1[i] = new char [size];
cout << size << endl;
char *tp = p1[i];
for ( int x =0 ; x< (size-1); x++)
{
//cout << x << endl;
*(tp+x) = char( (x%26)+ 48);

}
*(tp+size-1) =0;
cout << "p [" << i << "]ok" << endl;
}

for (int i =0 ; i < len ;i++)
{
delete [] p1[i];
}
return 0;
}
////////////////////////////////////////////

[Martin Ambuhl]

ch***********@h otmail.com wrote:

hi
i try to malloc 2G size mem . so i wirte code like that.
You have no guarantee that you can do so. You need to check in a
newsgroup, mailing list, or tech support for your implementation.
it failt in freebsd 5.3 and win2k
what's bug in my code ? how can i change it ?
We really can't help, partially because you posted to comp.lang.c, where
we use C, and your code is not C. comp.lang.c++ is a different newsgroup
for a different language.

Examples of C++isms are: #include <iostream> This is not a C header. using namespace std; This is a compilation error. #include <cstdlib> This is not a C header. cout << size << endl; 'cout' and 'endl' are undeclared identifiers, and '<<' is a
left-shift operator that probably don't do what you want. p1[i] = new char [size];

'new' is an undeclared identifier, and the above is a compilation error.

There are more instances, but I don't care to be tiresome.

[Walter Roberson]

In article <d1**********@n ews.yaako.com>, <ch***********@ hotmail.com> wrote:
: i try to malloc 2G size mem . so i wirte code like that.
:it failt in freebsd 5.3 and win2k

:what's bug in my code ? how can i change it ?

And how are you compiling? It is fairly common for there to be a 2 GB
process size limit unless you specifically compile to use 64 bit
pointers. Yes, in theory with 32 bits you -could- get to 4 GB instead
of 2 GB, but it is not uncommon for half of the memory to be reserved
for system pointers.

Even within the 2 GB limit, it is common for there to be address space
layout issues: it is common for your code not to be placed at address 0
in virtual memory, and it is common for there to be an area reserved
for the stack, and it is common for there to be an area reserved for
the heap, and it is common for there to be one or more areas reserved
for DLLs or equivilent. You may have to give special linking options or
run special post-processors on the executable image in order to move
these reserved areas to give yourself the maximum amount of room.

On Unix systems it is also common for there to be resource limits that
prevent you from using gobs of memory unless you override them or get
the systems administrator to override them. See the 'ulimit' man page
to get yourself started, and the getrlimit() functions. The mechanisms
used by the systems administrator to control the limit would very with
unix version; I do not know the details for freebsd.

--
Entropy is the logarithm of probability -- Boltzmann

sorry! i am not prepense
i write it in c , and comp it under win2k and freebsd5.3

in freebsd
p [ 294 ] ok
1048576
Killed
///////////////////////////////////////////
#include <stdio.h>
#include <stdlib.h>
const int len = 2000;
int main()
{
char* p1[len];
int i =0;
int x =0;
static int size = 1<<20;
printf( "%d \n", size);
for ( i =0 ; i < len ;i++)
{
p1[i] = (char*) malloc (size);
printf( "%d \n", size );
char *tp = p1[i];
for ( x =0 ; x< (size-1); x++)
{
//cout << x << endl;
*(tp+x) = (char)( (x%26)+ 48);

}
*(tp+size-1) =0;
printf( "p [ %d ] ok\n" , i);
}

for ( i =0 ; i < len ;i++)
{
free(p1[i]);
}
return 0;
}

//////////////////////////////////////////

"Martin Ambuhl" <ma*****@earthl ink.net>
??????:u6****** *******@newsrea d2.news.atl.ear thlink.net...

ch***********@h otmail.com wrote:

hi
i try to malloc 2G size mem . so i wirte code like that.
You have no guarantee that you can do so. You need to check in a
newsgroup, mailing list, or tech support for your implementation.

it failt in freebsd 5.3 and win2k
what's bug in my code ? how can i change it ?

We really can't help, partially because you posted to comp.lang.c, where
we use C, and your code is not C. comp.lang.c++ is a different newsgroup
for a different language.

Examples of C++isms are:

#include <iostream>

This is not a C header.

using namespace std;

This is a compilation error.

#include <cstdlib>

This is not a C header.

cout << size << endl;

'cout' and 'endl' are undeclared identifiers, and '<<' is a
left-shift operator that probably don't do what you want.

p1[i] = new char [size];

'new' is an undeclared identifier, and the above is a compilation

error.
There are more instances, but I don't care to be tiresome.

[CBFalconer]

ch***********@h otmail.com wrote:

.... snip ... #include <iostream>
using namespace std;

comp.lang.c++ is down the hall to the right.

--
"I conclude that there are two ways of constructing a software
design: One way is to make it so simple that there are obviously
no deficiencies and the other way is to make it so complicated
that there are no obvious deficiencies." -- C. A. R. Hoare

[Raymond Martineau]

On Tue, 22 Mar 2005 16:35:15 +0800, <ch***********@ hotmail.com> wrote:

sorry! i am not prepense
i write it in c , and comp it under win2k and freebsd5.3

in freebsd
p [ 294 ] ok
1048576
Killed
/////////////////////////////////////////// [...]
p1[i] = (char*) malloc (size);

This causes undefined behaviour when malloc returns NULL. Check the return
value.

[Jonathan Bartlett]

ch***********@h otmail.com wrote:

hi
i try to malloc 2G size mem . so i wirte code like that.
it failt in freebsd 5.3 and win2k

what's bug in my code ? how can i change it ?

I don't know about FreeBSD, but on Windows a process cannot be bigger
than 2G, even if you have more RAM than that. Each process is limitted
to at most 2G. So, if you add the space for your code, libraries, and
existing variables, malloc'ing 2G on a Windows box is guaranteed to fail.

I _think_ Linux gives you 3G, but I could be wrong. I don't know if
these limits persist to AMD-64 or not. However, I would try it on a
64-bit PowerPC -- it should work there.

Jon
----
Learn to program using Linux assembly language
http://www.cafeshops.com/bartlettpublish.8640017

[CBFalconer]

Raymond Martineau wrote:

<ch***********@ hotmail.com> wrote:
.... snip ...

p1[i] = (char*) malloc (size);

This causes undefined behaviour when malloc returns NULL. Check
the return value.

No it doesn't. NULL is a perfectly valid value for a char*.
However the useless cast can conceal errors, and should be avoided.

However, there may be a later problem when using p[i].

--
"I conclude that there are two ways of constructing a software
design: One way is to make it so simple that there are obviously
no deficiencies and the other way is to make it so complicated
that there are no obvious deficiencies." -- C. A. R. Hoare

[Christopher Benson-Manica]

CBFalconer <cb********@yah oo.com> spoke thus:

No it doesn't. NULL is a perfectly valid value for a char*.
However the useless cast can conceal errors, and should be avoided. However, there may be a later problem when using p[i].

I think this is what he was actually referring to, although his
quoting could have been better.

--
Christopher Benson-Manica | I *should* know what I'm talking about - if I
ataru(at)cybers pace.org | don't, I need to know. Flames welcome.

#include <stdio.h>

#include <stdlib.h>
const int len = 2000;
int main()
{
char* p1[len];
int i =0;
int x =0;
static int size = 1<<20;
printf( "%d \n", size);
for ( i =0 ; i < len ;i++)
{
p1[i] = (char*) malloc (size);
printf( "%d \n", size );
char *tp = p1[i];
for ( x =0 ; x< (size-1); x++)
{
//cout << x << endl;
*(tp+x) = (char)( (x%26)+ 48);

}
*(tp+size-1) =0;
printf( "p [ %d ] ok\n" , i);
}

for ( i =0 ; i < len ;i++)
{
free(p1[i]);
}
return 0;
}