Hello,
gcc 3.4.3 compiles and links the following code successfully:
#include <iostream>
class X
{};
template <typename T>
void g (const T & t)
{
std::cout << "Function g was called" << std::endl;
}
template <typename T>
void f()
{
T a;
g<typename S>(a); // <--------------- Crucial line
}
int
main(int argc, char* argv[])
{
f<X>();
}
//
-----------------------------------------------------------------------------
The ggc compiles and links this code without an error. The execution of this
code does NOT write the output of function g "Function g was called", so
function g is apparently not called.
What does gcc do with the line "g<typename S>(a)"?
Shouldn't it report an error, since there is no type S defined anywhere?
Shouldn't gcc reject the word "typname" in an explicit function template
argument specification?
Maybe it has something to do with the "two-stage name lookup", because if we
make the crucial line not dependent on the template parameter by just replacing
T with X in the previous line, the gcc suddenly reports an error saying:
test.cxx: In function `void f()':
test.cxx:23: error: template argument 1 is invalid
test.cxx:23: error: no matching function for call to `g(X&)'
Compiler and Environment Details:
=================================
$ g++ -v -save-temps test.cxx
Reading specs from /usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/specs
Configured with: /usr/gcc-3.4.3/configure --enable-languages=c,c++
--prefix=/usr/local/gcc-3.4.3
Thread model: posix
gcc version 3.4.3
/usr/local/gcc-3.4.3/libexec/gcc/i686-pc-linux-gnu/3.4.3/cc1plus -E -quiet -v
-D_GNU_SOURCE test.cxx -mtune=pentiumpro -o test.ii
ignoring nonexistent directory
"/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/../../../../i686-pc-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/../../../../include/c++/3.4.3
/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/../../../../include/c++/3.4.3/i686-pc-linux-gnu
/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/../../../../include/c++/3.4.3/backward
/usr/local/include
/usr/local/gcc-3.4.3/include
/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/include
/usr/include
End of search list.
/usr/local/gcc-3.4.3/libexec/gcc/i686-pc-linux-gnu/3.4.3/cc1plus
-fpreprocessed test.ii -quiet -dumpbase test.cxx -mtune=pentiumpro -auxbase
test -version -o test.s
GNU C++ version 3.4.3 (i686-pc-linux-gnu)
compiled by GNU C version 3.4.3.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
as -V -Qy -o test.o test.s
GNU assembler version 2.14.90.0.4 (i386-redhat-linux) using BFD version
2.14.90.0.4 20030523
/usr/local/gcc-3.4.3/libexec/gcc/i686-pc-linux-gnu/3.4.3/collect2
--eh-frame-hdr -m elf_i386 -dynamic-linker /lib/ld-linux.so.2 /usr/lib/crt1.o
/usr/lib/crti.o /usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/crtbegin.o
-L/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3
-L/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/../../.. test.o -lstdc++
-lm -lgcc_s -lgcc -lc -lgcc_s -lgcc
/usr/local/gcc-3.4.3/lib/gcc/i686-pc-linux-gnu/3.4.3/crtend.o /usr/lib/crtn.o
--
Summary: "typename" in explicit template argument specification
Product: gcc
Version: 3.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: o dot kwak at rtsgroup dot net
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26380
