A template class member function that is defined out-of-line with an
associated explicit template instantiation is not instantiated by g++ 4.0.x.
No warnings or error messages are given. Using earlier g++ versions, the
member function is instantiated and placed in the object file.
Confirmed function is instantiated with
g++ 3.3.0/linux, 3.4.4/cygwin
Confirmed function is not instantiated with
g++ 4.0.1/linux, 4.0.2/linux
Source:
// ATemplate.h
template <class T>
class ATemplate
{
T const n;
public:
ATemplate () : n (1) { }
T GetValue () const;
};
template class ATemplate<int>;
// ATemplate.cpp
#include "ATemplate.h"
template <class T>
T ATemplate<T>::GetValue () const
{
return n;
}
Compile:
% g++ -c ATemplate.cpp
Contents of object file:
-----
g++ 3.4.4 (cygwin):
% g++ -v
Reading specs from /usr/lib/gcc/i686-pc-cygwin/3.4.4/specs
Configured with: /gcc/gcc-3.4.4/gcc-3.4.4-1/configure --verbose --prefix=/usr
--exec-prefix=/usr --sysconfdir=
/etc --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man
--infodir=/usr/share/info --enable-langua
ges=c,ada,c++,d,f77,java,objc --enable-nls --without-included-gettext
--enable-version-specific-runtime-libs -
-without-x --enable-libgcj --disable-java-awt --with-system-zlib
--enable-interpreter --disable-libgcj-debug -
-enable-threads=posix --enable-java-gc=boehm --disable-win32-registry
--enable-sjlj-exceptions --enable-hash-s
ynchronization --enable-libstdcxx-debug : (reconfigured)
Thread model: posix
gcc version 3.4.4 (cygming special) (gdc 0.12, using dmd 0.125)
% nm -C ATemplate.o
00000000 T ATemplate<int>::ATemplate()
00000000 T ATemplate<int>::ATemplate()
00000000 T ATemplate<int>::GetValue() const
-----
g++ 4.0.1 (Linux x86_64):
% g++ -v
Using built-in specs.
Target: x86_64-unknown-linux-gnu
Configured with: /home/nrel/ty/build/devel/gcc/gcc-4.0.1/configure
--prefix=/usr2/OS-DEPENDENT/Linux_Generic_x86_64/gcc-4.0.1
Thread model: posix
gcc version 4.0.1
% nm -C ATemplate.o
0000000000000000 W ATemplate<int>::ATemplate()
0000000000000000 W ATemplate<int>::ATemplate()
U __gxx_personality_v0
--
Summary: template class method defined out-of-line is not
instantiated
Product: gcc
Version: 4.0.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tom dot hilinski at comcast dot net
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26786
