Trying to compile the following code on a FreeBSD 5.4 machine, using GCC 4.0.1.... # 1 "Test.cpp" # 0 "<built-in>" # 1 "<command line>" # 1 "Test.cpp" class OutStream { public: OutStream(); }; inline OutStream & operator<<( OutStream & output, const int & value ) { return output; } class Client { public: OutStream send() { return OutStream(); } }; int main(int argc,char **argv) { Client myclient; int x = 32; int y = 64; myclient.send() << x << y; return 0; } Produces the following output... Using built-in specs. Target: i386-portbld-freebsd5.4 Configured with: ./..//gcc-4.1-20050730/configure --disable-nls --with-system- zlib --with-libiconv-prefix=/usr/local --program-suffix=41 -- libdir=/usr/local/lib/gcc/i386-portbld-freebsd5.4/4.1.0 --with-gxx-include- dir=/usr/local/lib/gcc/i386-portbld-freebsd5.4/4.1.0/include/c++/ --disable- shared --disable-rpath --prefix=/usr/local i386-portbld-freebsd5.4 Thread model: posix gcc version 4.1.0 20050730 (experimental) /usr/local/libexec/gcc/i386-portbld-freebsd5.4/4.1.0/cc1plus -E -quiet -v Test.cpp -fpch-preprocess -o Test.ii ignoring nonexistent directory "/usr/local/lib/gcc/i386-portbld- freebsd5.4/4.1.0/gcc/i386-portbld-freebsd5.4/4.1.0/../../../../i386-portbld- freebsd5.4/include" #include "..." search starts here: #include <...> search starts here: /usr/local/lib/gcc/i386-portbld-freebsd5.4/4.1.0/include/c++/ /usr/local/lib/gcc/i386-portbld-freebsd5.4/4.1.0/include/c++//i386-portbld- freebsd5.4 /usr/local/lib/gcc/i386-portbld-freebsd5.4/4.1.0/include/c++//backward /usr/local/include /usr/local/lib/gcc/i386-portbld-freebsd5.4/4.1.0/gcc/i386-portbld- freebsd5.4/4.1.0/include /usr/include End of search list. /usr/local/libexec/gcc/i386-portbld-freebsd5.4/4.1.0/cc1plus -fpreprocessed Test.ii -quiet -dumpbase Test.cpp -auxbase Test -version -o Test.s GNU C++ version 4.1.0 20050730 (experimental) (i386-portbld-freebsd5.4) compiled by GNU C version 4.1.0 20050730 (experimental). GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096 Compiler executable checksum: c62afa56bfea22d68bd8bf2d1f862a27 Test.cpp: In function 'int main(int, char**)': Test.cpp:33: error: no match for 'operator<<' in 'myclient. Client::send() << x' Test.cpp:11: note: candidates are: OutStream& operator<<(OutStream&, const int&)
Not a bug as you cannot bind a rvalue to the reference type. Basicially what you have is: int g(void); void h(int&); void j(void) { h(g()); } And that is invalid. You can bind a rvalue to a const reference type though.