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* [Bug c++/29148] New: can't subtract 'volatile char *' from 'const char *'
@ 2006-09-20 11:47 andrew dot stubbs at st dot com
2006-09-20 12:58 ` [Bug c++/29148] " rguenth at gcc dot gnu dot org
0 siblings, 1 reply; 3+ messages in thread
From: andrew dot stubbs at st dot com @ 2006-09-20 11:47 UTC (permalink / raw)
To: gcc-bugs
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#include <stdio.h>
char str[] = "abc";
const char *a1 = str;
struct A { operator const char *() {return str;} } a2;
volatile char *b1 = str;
struct B { operator volatile char *() {return str;} } b2;
int
main()
{
printf ("%p\n", a1);
printf ("%p\n", b1);
printf ("%p\n", (const char *)a2);
printf ("%p\n", (volatile char *)b2);
printf ("%d\n", a1 - b1);
printf ("%d\n", (const char *)a2 - (volatile char *)b2);
printf ("%d\n", a2 - b2); // error reported here
return 0;
}
gives:
t.cpp: In function int main():
t.cpp:22: error: no match for operator- in a2 - b2
t.cpp:22: note: candidates are: operator-(volatile char*, volatile char*)
<built-in>
t.cpp:22: note: operator-(const char*, const char*) <built-in>
However, lines 20 and 21 clearly do the same operation, but slightly
differently. These lines appear to be able to convert the types, presumably
according to clause 4.4 of the C++ standard, but the last example cannot. Yet
the error message shows that it has found the right conversion operators.
EDG 3.0 compiles this without any issues.
Note: the correct behaviour of this program is to print the same pointer four
times, and then print zero three times.
--
Summary: can't subtract 'volatile char *' from 'const char *'
Product: gcc
Version: 4.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: andrew dot stubbs at st dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29148
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/29148] can't subtract 'volatile char *' from 'const char *'
2006-09-20 11:47 [Bug c++/29148] New: can't subtract 'volatile char *' from 'const char *' andrew dot stubbs at st dot com
@ 2006-09-20 12:58 ` rguenth at gcc dot gnu dot org
0 siblings, 0 replies; 3+ messages in thread
From: rguenth at gcc dot gnu dot org @ 2006-09-20 12:58 UTC (permalink / raw)
To: gcc-bugs
------- Comment #1 from rguenth at gcc dot gnu dot org 2006-09-20 12:58 -------
Confirmed.
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Keywords| |rejects-valid
Last reconfirmed|0000-00-00 00:00:00 |2006-09-20 12:58:20
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29148
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/29148] can't subtract 'volatile char *' from 'const char *'
[not found] <bug-29148-4@http.gcc.gnu.org/bugzilla/>
@ 2011-10-12 21:40 ` paolo.carlini at oracle dot com
0 siblings, 0 replies; 3+ messages in thread
From: paolo.carlini at oracle dot com @ 2011-10-12 21:40 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29148
Paolo Carlini <paolo.carlini at oracle dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC|gcc-bugs at gcc dot gnu.org |
Resolution| |DUPLICATE
Known to fail| |
--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-12 21:37:54 UTC ---
Closing as duplicate.
*** This bug has been marked as a duplicate of bug 38174 ***
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-10-12 21:40 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2006-09-20 11:47 [Bug c++/29148] New: can't subtract 'volatile char *' from 'const char *' andrew dot stubbs at st dot com
2006-09-20 12:58 ` [Bug c++/29148] " rguenth at gcc dot gnu dot org
[not found] <bug-29148-4@http.gcc.gnu.org/bugzilla/>
2011-10-12 21:40 ` paolo.carlini at oracle dot com
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