Hello,
I'd like to point your attention to a weird linker error I see on my system
on gcc version 4.3.3, 4.4.1 and 4.4.2.
I could not find anything related to this in bugzilla using the keyword
typedef.
Here are three files I use to produce the error:
/*
* bug.cpp
*
* Created on: 07.11.2009
* Author: Wolf Lammen
*/
#include "A.h"
int main()
{
A::B().foo();
return 0;
}
===========================================================================
/*
* A.h
*
* Created on: 07.11.2009
* Author: Wolf Lammen
*/
/*
* this compiles and links fine, if I
* a) inline foo i.e use "void foo(){}" and remove foo() from A.cpp
* b) avoid the keyword typedef and use "struct B { void foo(); };" instead
*/
struct A {
typedef struct {
void foo();
} B;
};
===========================================================================
/*
* A.cpp
*
* Created on: 07.11.2009
* Author: Wolf Lammen
*/
#include "A.h"
void A::B::foo() {}
===========================================================================
Here's the output I get with g++, latest version
(similar for 4.3.3 or 4.4.1)
w...@kubuntu-910:~/bug$ ../bin/gcc-4.4.2/bin/g++ --version
Copyright (C) 2009 Free Software Foundation, Inc.
Dies ist freie Software; die Kopierbedingungen stehen in den Quellen. Es
gibt KEINE Garantie; auch nicht für MARKTGÄNGIGKEIT oder FÜR SPEZIELLE ZWECKE.
w...@kubuntu-910:~/bug$ cat A.h
/*
* A.h
*
* Created on: 07.11.2009
* Author: Wolf Lammen
*/
/*
* this compiles fine, if I
* a) inline foo i.e use void foo(){} and remove foo() from A.cpp
* b) avoid the keyword typedef and use struct B { void foo(); }; instead
*/
struct A {
typedef struct {
void foo();
} B;
};
w...@kubuntu-910:~/bug$ ~/bin/gcc-4.4.2/bin/g++ -O0 -g3 -Wall -c
-fmessage-length=0 -MMD -MP -MF"A.d" -MT"A.d" -o"A.o" "A.cpp"
w...@kubuntu-910:~/bug$ ../bin/gcc-4.4.2/bin/g++ -O0 -g3 -Wall -c
-fmessage-length=0 -MMD -MP -MF"bug.d" -MT"bug.d" -o"bug.o" "bug.cpp"
w...@kubuntu-910:~/bug$ ../bin/gcc-4.4.2/bin/g++ -o"test" ./A.o ./bug.o
./bug.o: In function `main':
/home/wolf/bug/bug.cpp:12: undefined reference to `A::B::foo()'
collect2: ld gab 1 als Ende-Status zurück
There is a simple work-around:
use
struct B{
void foo();
};
instead of the typedef struct {...} in file A.h, and everything compiles
and links fine (see below):
w...@kubuntu-910:~/bug$ ../bin/gcc-4.4.2/bin/g++ --version
g++ (GCC) 4.4.2
Copyright (C) 2009 Free Software Foundation, Inc.
Dies ist freie Software; die Kopierbedingungen stehen in den Quellen. Es
gibt KEINE Garantie; auch nicht für MARKTGÄNGIGKEIT oder FÜR SPEZIELLE ZWECKE.
w...@kubuntu-910:~/bug$ ~/bin/gcc-4.4.2/bin/g++ -O0 -g3 -Wall -c
-fmessage-length=0 -MMD -MP -MF"A.d" -MT"A.d" -o"A.o" "A.cpp"
w...@kubuntu-910:~/bug$ ../bin/gcc-4.4.2/bin/g++ -O0 -g3 -Wall -c
-fmessage-length=0 -MMD -MP -MF"bug.d" -MT"bug.d" -o"bug.o" "bug.cpp"
w...@kubuntu-910:~/bug$ ../bin/gcc-4.4.2/bin/g++ -o"test" ./A.o ./bug.o
w...@kubuntu-910:~/bug$ cat A.h
/*
* A.h
*
* Created on: 07.11.2009
* Author: Wolf Lammen
*/
/*
* this compiles fine, if I
* a) inline foo i.e use void foo(){} and remove foo() from A.cpp
* b) avoid the keyword typedef and use struct B { void foo(); }; instead
*/
struct A {
struct B{
void foo();
};
};
Although there is a simple work-around (with slightly different semantics), the
example is AFAIK correct C++ code, that shouldn't rise any problems.
cheers
Wolf Lammen
--
Summary: linker error with typedef struct
Product: gcc
Version: 4.4.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: ookami1 at gmx dot de
GCC build triplet: x86_64-unknown-linux-gnu
GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42011
