Hi,
.. following causes a segfault. .. didn't
know why ?!
int main() {
char name[15];
strcpy (name, "ab8bc8cd8e d");
char cur[800];
strcpy (cur, strtok(name, "8"));
while (cur) {
printf ("Output: %s\n", cur);
printf ("Stringleng th %i\n", strlen(cur));
strcpy(cur,strt ok(0, "8"));
printf ("next\n");
}
}
output: -----------------------
Output: ab
Stringlength 2
next
Output: bc
Stringlength 2
next
Output: cd
Stringlength 2
next
Output: ed
Stringlength 2
Segmentationfau lt
------------------------------
Thanks for any help
Regards
Fatih Gey
Nov 13 '05
40  3526 
On Sun, 26 Oct 2003 23:06:08 +0000, Mark McIntyre wrote: On Sat, 25 Oct 2003 19:22:11 -0400, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote:
It seems like you don't really "get" the fact...
I "get" it perfectly. Its just that zero is an integer, and letting
the compiler implicitly convert it to a void* so that you can compare
to a pointer, while syntactically fine, doesn't sit well with me.
The compiler does the same thing whether or not you use the NULL
macro: It recognizes a null pointer constant and converts it to a
null pointer if used in a pointer context. If not used in a pointer
context, the 0 is an integer constant. Using NULL instead of 0
doesn't affect this at all.
Anyway, YMMV
True.
HAND, OAO.
Roger.
On Sun, 26 Oct 2003 20:13:06 -0500, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote: On Sun, 26 Oct 2003 23:06:08 +0000, Mark McIntyre wrote:
On Sat, 25 Oct 2003 19:22:11 -0400, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote:
It seems like you don't really "get" the fact...
I "get" it perfectly. Its just that zero is an integer, and letting
the compiler implicitly convert it to a void* so that you can compare
to a pointer, while syntactically fine, doesn't sit well with me.
The compiler does the same thing whether or not you use the NULL
macro:
You miss the point. This is nothing to do with the compiler. The
compiler probably also recognises
int* p = ((long)100000 - (long)pow(10,5) );
as meaning "set p to a null pointer"
that doesn't mean to say its a good idea to use this definition of
NULL, purely from a point of view of clarity of code.
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.angelfire.c om/ms3/bchambless0/welcome_to_clc. html>
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Mark McIntyre wrote: You miss the point. This is nothing to do with the compiler. The
compiler probably also recognises
int* p = ((long)100000 - (long)pow(10,5) );
as meaning "set p to a null pointer"
I doubt it. That doesn't look much an integer constant expression.
Jeremy.
On Mon, 27 Oct 2003 22:47:55 +0000, Mark McIntyre wrote: On Sun, 26 Oct 2003 20:13:06 -0500, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote:
On Sun, 26 Oct 2003 23:06:08 +0000, Mark McIntyre wrote:
On Sat, 25 Oct 2003 19:22:11 -0400, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote:
It seems like you don't really "get" the fact...
I "get" it perfectly. Its just that zero is an integer, and letting
the compiler implicitly convert it to a void* so that you can compare
to a pointer, while syntactically fine, doesn't sit well with me.
The compiler does the same thing whether or not you use the NULL
macro:
You miss the point. This is nothing to do with the compiler.
Then why did you mention it?
On 27 Oct 2003 23:16:22 GMT, in comp.lang.c , Jeremy Yallop
<je****@jdyallo p.freeserve.co. uk> wrote: Mark McIntyre wrote: You miss the point. This is nothing to do with the compiler. The
compiler probably also recognises
int* p = ((long)100000 - (long)pow(10,5) );
as meaning "set p to a null pointer"
I doubt it. That doesn't look much an integer constant expression.
depends how pow is implemented :-)
but you're right. replace pow with 10*10*10*10*10
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.angelfire.c om/ms3/bchambless0/welcome_to_clc. html>
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On Mon, 27 Oct 2003 19:48:41 -0500, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote: On Mon, 27 Oct 2003 22:47:55 +0000, Mark McIntyre wrote:
On Sun, 26 Oct 2003 20:13:06 -0500, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote:
On Sun, 26 Oct 2003 23:06:08 +0000, Mark McIntyre wrote:
The compiler does the same thing whether or not you use the NULL
macro:
You miss the point. This is nothing to do with the compiler.
Then why did you mention it?
I didn't mention the compiler, you brought that up.
Shall we continue to psephologise?
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.angelfire.c om/ms3/bchambless0/welcome_to_clc. html>
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Restoring Context...
On Tue, 28 Oct 2003 18:51:00 +0000, Mark McIntyre wrote: On Mon, 27 Oct 2003 19:48:41 -0500, Sheldon Simms wrote:
On Mon, 27 Oct 2003 22:47:55 +0000, Mark McIntyre wrote:
On Sun, 26 Oct 2003 20:13:06 -0500, Sheldon Simms wrote:
On Sun, 26 Oct 2003 23:06:08 +0000, Mark McIntyre wrote:
>On Sat, 25 Oct 2003 19:22:11 -0400, Sheldon Simms wrote:
>
>>On Sat, 25 Oct 2003 23:02:12 +0100, Mark McIntyre wrote:
>>
>>> *shrug*. For me, I find it counterintuitiv e to say "if pointer is
>>> zero" when I mean "if pointer is a null pointer", since pointers
>>> aren't numbers, they're pointers.
>>
>>It seems like you don't really "get" the fact that
>
> I "get" it perfectly. Its just that zero is an integer, and
> letting the compiler implicitly convert it to a void* so that
^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^> you can compare to a pointer, while syntactically fine, doesn't
^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^> sit well with me.
^^^^^^^^^^^^^^^ ^
The compiler does the same thing whether or not you use the NULL
macro:
You miss the point. This is nothing to do with the compiler.
Then why did you mention it?
I didn't mention the compiler, you brought that up.
No I didn't. You said that letting the compiler do a conversion
"doesn't sit well with you". I just pointed out that the compiler
does the same thing whether you use the null pointer constant 0,
or you use the macro NULL, because the macro NULL contains a
null pointer constant with the textual representation "0".
Shall we continue to psephologise?
Well since we aren't psephologizing (if there is such a word),
we can't continue. Why would we want to study elections in
comp.lang.c anyway?
On Tue, 28 Oct 2003 20:47:41 -0500, in comp.lang.c , Sheldon Simms
<sh**********@y ahoo.com> wrote:
Restoring Context...
On Tue, 28 Oct 2003 18:51:00 +0000, Mark McIntyre wrote:
On Mon, 27 Oct 2003 19:48:41 -0500, Sheldon Simms wrote:
On Mon, 27 Oct 2003 22:47:55 +0000, Mark McIntyre wrote:
On Sun, 26 Oct 2003 20:13:06 -0500, Sheldon Simms wrote:
>On Sun, 26 Oct 2003 23:06:08 +0000, Mark McIntyre wrote:
>
>>On Sat, 25 Oct 2003 19:22:11 -0400, Sheldon Simms wrote:
>>
>>>On Sat, 25 Oct 2003 23:02:12 +0100, Mark McIntyre wrote:
>>>
>>>> *shrug*. For me, I find it counterintuitiv e to say "if pointer is
>>>> zero" when I mean "if pointer is a null pointer", since pointers
>>>> aren't numbers, they're pointers.
>>>
>>>It seems like you don't really "get" the fact that
>>
>> I "get" it perfectly. Its just that zero is an integer, and
>> letting the compiler implicitly convert it to a void* so that ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^>> you can compare to a pointer, while syntactically fine, doesn't ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^ ^^^>> sit well with me. ^^^^^^^^^^^^^^^ ^>
>The compiler does the same thing whether or not you use the NULL
>macro:
You miss the point. This is nothing to do with the compiler.
Then why did you mention it?
I didn't mention the compiler, you brought that up.
No I didn't. You said that letting the compiler do a conversion
"doesn't sit well with you".
So? I didn't say that my point had anything to do with the compiler.
I just pointed out
yada yada. Nobody's listening to us.
We disagree, I happen to think that its needlessly obfuscating to use
zero to mean a null pointer when there's a perfectly good macro
provided for it. You disagree for no obvious reason I can discern.
Enough.
Shall we continue to psephologise?
Well since we aren't psephologizing (if there is such a word),
we can't continue. Why would we want to study elections in
comp.lang.c anyway?
Perhaps filibustering is closer to the mark. We're both trying to talk
the other into the ground, without actually forcing any conclusion,
because there /is/ no conclusion.
--
Mark McIntyre
CLC FAQ <http://www.eskimo.com/~scs/C-faq/top.html>
CLC readme: <http://www.angelfire.c om/ms3/bchambless0/welcome_to_clc. html>
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Mark McIntyre <ma**********@s pamcop.net> wrote: Sheldon Simms <sh**********@y ahoo.com> wrote:
<snip>yada yada. Nobody's listening to us.
Not true, it's kind of amusing. ;-)
<snip> Shall we continue to psephologise?
<snip>
Perhaps filibustering is closer to the mark.
<snip>
And one can learn interesting words, too. ;-)
--
Irrwahn,
prefers NULL over 0 in pointer contexts.
On Thu, 30 Oct 2003 00:29:03 +0100, Irrwahn Grausewitz wrote: Mark McIntyre <ma**********@s pamcop.net> wrote:
Sheldon Simms <sh**********@y ahoo.com> wrote:
<snip>yada yada. Nobody's listening to us.
Not true, it's kind of amusing. ;-)
And besides, the thread reaches only halfway to the
the right side of the window. It would be a shame to
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