AMD opteron 64

[Lionel Valero]

Hello,

I have a test program that is compiled fine on a 32 bits redhat linux using gcc :
***********************
main (argc, argv)
int argc;
char *argv[];
{
int *ka;
int nka;

/* allocation dynamique entiere */
ka = (int *) malloc(nka * sizeof(int));
if (!ka) {
printf ("<ERROR> : Out of heap space (malloc) !\n");
printf ("<ERROR> : %d int words required\n", nka);
exit (-1);
}
}
***********************

But under linux suse AMD opteron 64, i get this message from the compiler :

warning: cast to pointer from integer of different size

Any explanation ?

Regards,
Lionel.
--
-=O=------------------------------------------=O=-
Lionel Valéro
Analyste Informatique Département Génie Chimique
École Polytechnique de Montréal
C.P. 6079, succ. centre-ville
Montréal (Québec) H3C 3A7
Tel: (514) 340 - 4711 # 4805 / C552
Fax: (514) 340 - 4159
-=O=------------------------------------------=O=-

[Grumble]

Eric Sosman wrote:

there never seems to be a shortage of people willing to point out
misteaks

I want mine rare, thanks! :-)

[Keith Thompson]

"E. Robert Tisdale" <E.**************@jpl.nasa.gov> writes:
[...]

If I find a great open source function library implemented in C,
a I obliged to re-implement in C++ so that "C++ folks"
will "deem it good code"? I don't think so.
I just compile it with my C++ compiler
and link it into my C++ programs.

Why not compile it with your C compiler and use extern "C"?

--
Keith Thompson (The_Other_Keith) ks***@mib.org <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://www.sdsc.edu/~kst>
Schroedinger does Shakespeare: "To be *and* not to be"
(Note new e-mail address)

[The Real OS/2 Guy]

On Thu, 4 Dec 2003 09:14:11 UTC, NFish <no****@nowhere.net> wrote:

The Real OS/2 Guy wrote:

On Mon, 1 Dec 2003 19:00:18 UTC, Lionel Valero
<li***********@polymtl.ca> wrote:

I forgto the headers :
#include <stdio.h>
#include <sys/types.h>
#include <time.h>

You forgot to include stdlib.h again

Lionel Valero wrote:

ka = (int *) malloc(nka * sizeof(int));

And this cast hides the error that you forgot to include the header in
redhat linux.
Casting the result from a function that returns void* is always an
error.

Well, I wouldn't go that far. Consider replacing the first occurrence
of 'a' with 'A" in a block of 100 bytes, given that it exists.

*(char*)memchr(buffer, 'a', sizeof buffer) = 'A';

seems like a reasonable solution.

You'll get 2 problems here:
1. you forgot to include string.h. results in a faulty conversion of
int to char*
as you supperess the diagnostic the compiler will give you.
2. memchr() may return NULL - results in dereferencing a NULL pointer.

Again: never cast the result of a function that returns pointer to
void because the only you get is a faulty program.

--
Tschau/Bye
Herbert

To buy eComStation 1.1 in germany visit http://www.pc-rosenau.de

[E. Robert Tisdale]

Keith Thompson wrote:

E. Robert Tisdale writes:
[...]

If I find a great open source function library implemented in C,
a I obliged to re-implement in C++ so that "C++ folks"
will "deem it good code"? I don't think so.
I just compile it with my C++ compiler
and link it into my C++ programs.

Why not compile it with your C compiler and use extern "C"?

extern "C" only *helps* with linkage.
There is no guarantee, for example, that both the C and C++ compiler
will use the same representation for int.
There is no guarantee that both compilers will pass (or return)
arguments in the same registers or on the stack in the same order.
The only reliable way to link C library functions into C++ programs
is to compile them both with the same C++ compiler.

[Randy Howard]

In article <3F************@jpl.nasa.gov>, E.**************@jpl.nasa.gov
says...

extern "C" only *helps* with linkage.
There is no guarantee, for example, that both the C and C++ compiler
will use the same representation for int.

Which platform(s) have C and C++ compilers where this does not work.
Please give a specific example, with example code to show the failure.

--
Randy Howard _o
2reply remove FOOBAR \<,
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