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* [Bug c++/26011] New: References to const pointers to const objects don't work as expected.
@ 2006-01-29 0:38 ciprian dot craciun at gmail dot com
2006-01-29 0:41 ` [Bug c++/26011] " ciprian dot craciun at gmail dot com
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: ciprian dot craciun at gmail dot com @ 2006-01-29 0:38 UTC (permalink / raw)
To: gcc-bugs
I think the best way to describe the problem is giving a simple piece of code:
int t1;
int t2;
int * a = &t1;
int const * const & b = a;
a = &t2;
printf ("test 2: %x %x\n", a, b);
if (a != b)
printf ("UPS!!!\n");
My gcc -v outputs:
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,java,f95,objc,ada,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--program-suffix=-4.0 --enable-__cxa_atexit --enable-clocale=gnu
--enable-libstdcxx-debug --enable-java-awt=gtk-default --enable-gtk-cairo
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-4.0-1.4.2.0/jre --enable-mpfr
--disable-werror --enable-checking=release i486-linux-gnu
Thread model: posix
gcc version 4.0.3 20051201 (prerelease) (Debian 4.0.2-5)
--
Summary: References to const pointers to const objects don't work
as expected.
Product: gcc
Version: 4.0.3
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: ciprian dot craciun at gmail dot com
GCC build triplet: 4.0.3
GCC target triplet: i486-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26011
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/26011] References to const pointers to const objects don't work as expected.
2006-01-29 0:38 [Bug c++/26011] New: References to const pointers to const objects don't work as expected ciprian dot craciun at gmail dot com
@ 2006-01-29 0:41 ` ciprian dot craciun at gmail dot com
2006-01-29 0:42 ` ciprian dot craciun at gmail dot com
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: ciprian dot craciun at gmail dot com @ 2006-01-29 0:41 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from ciprian dot craciun at gmail dot com 2006-01-29 00:41 -------
Created an attachment (id=10752)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10752&action=view)
The preprocessed file that exemplifies the bug.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26011
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/26011] References to const pointers to const objects don't work as expected.
2006-01-29 0:38 [Bug c++/26011] New: References to const pointers to const objects don't work as expected ciprian dot craciun at gmail dot com
2006-01-29 0:41 ` [Bug c++/26011] " ciprian dot craciun at gmail dot com
@ 2006-01-29 0:42 ` ciprian dot craciun at gmail dot com
2006-01-29 1:38 ` pinskia at gcc dot gnu dot org
2006-01-29 9:31 ` ciprian dot craciun at gmail dot com
3 siblings, 0 replies; 5+ messages in thread
From: ciprian dot craciun at gmail dot com @ 2006-01-29 0:42 UTC (permalink / raw)
To: gcc-bugs
------- Comment #2 from ciprian dot craciun at gmail dot com 2006-01-29 00:42 -------
Created an attachment (id=10753)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=10753&action=view)
The original source code file that exemplifies the bug.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26011
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/26011] References to const pointers to const objects don't work as expected.
2006-01-29 0:38 [Bug c++/26011] New: References to const pointers to const objects don't work as expected ciprian dot craciun at gmail dot com
2006-01-29 0:41 ` [Bug c++/26011] " ciprian dot craciun at gmail dot com
2006-01-29 0:42 ` ciprian dot craciun at gmail dot com
@ 2006-01-29 1:38 ` pinskia at gcc dot gnu dot org
2006-01-29 9:31 ` ciprian dot craciun at gmail dot com
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2006-01-29 1:38 UTC (permalink / raw)
To: gcc-bugs
------- Comment #3 from pinskia at gcc dot gnu dot org 2006-01-29 01:38 -------
int t1;
int t2;
int * a = &t1;
int const * const & b = a;
----
This does something different than you think.
It creates a temparory variable for the type, "const int *" as you need to
first convert a to that and then to "const int * const" as "const int * const"
is not compatiable with "int *".
--
pinskia at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26011
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/26011] References to const pointers to const objects don't work as expected.
2006-01-29 0:38 [Bug c++/26011] New: References to const pointers to const objects don't work as expected ciprian dot craciun at gmail dot com
` (2 preceding siblings ...)
2006-01-29 1:38 ` pinskia at gcc dot gnu dot org
@ 2006-01-29 9:31 ` ciprian dot craciun at gmail dot com
3 siblings, 0 replies; 5+ messages in thread
From: ciprian dot craciun at gmail dot com @ 2006-01-29 9:31 UTC (permalink / raw)
To: gcc-bugs
------- Comment #4 from ciprian dot craciun at gmail dot com 2006-01-29 09:31 -------
(In reply to comment #3)
> int t1;
> int t2;
>
> int * a = &t1;
> int const * const & b = a;
> ----
> This does something different than you think.
> It creates a temparory variable for the type, "const int *" as you need to
> first convert a to that and then to "const int * const" as "const int * const"
> is not compatiable with "int *".
>
Please scuse me to bother you, but your explanation doesn't seem right.
If I try:
int * a = 0;
int const * const b = a;
it compiles and even using the -Wall option the compiler does'nt complain.
Also if I try:
int t1;
int * a = &t1;
int const * & b = a;
it gives a compile time error... But I think the code is corect.
You said that int * is not compatible with int const * const (I know they
are compatible), but here I use int * as a int const *, which to my knowledge
are compatible (and used without & it compiles without errors).
These situations are exemplified in the file (bug-01.cpp) I have atached...
All I want to do is declare an alias to a variable, and weaken the access
to this alias. This is a valid operation. This is done in a class:
class astring { // ascii string
public :
astring (void) : length (actual_length), chars (actual_chars) {}
size_t const * length; // an alias to actual_length
char const * const & chars; // an alias to actual_chars
private :
size_t actual_length;
char * actual_chars;
};
length works fine when I update actual_length. Only chars don't get updated
when I update actual_chars.
--
ciprian dot craciun at gmail dot com changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ciprian dot craciun at gmail
| |dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26011
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2006-01-29 9:31 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2006-01-29 0:38 [Bug c++/26011] New: References to const pointers to const objects don't work as expected ciprian dot craciun at gmail dot com
2006-01-29 0:41 ` [Bug c++/26011] " ciprian dot craciun at gmail dot com
2006-01-29 0:42 ` ciprian dot craciun at gmail dot com
2006-01-29 1:38 ` pinskia at gcc dot gnu dot org
2006-01-29 9:31 ` ciprian dot craciun at gmail dot com
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