Rationale of non-const reference to temporaries

Hello,

I would like to submit the following code to your attention:

#include <string>
#include <iostream>

void f(std::string& s)
{ std::cout << s << std::endl; }

int main(int argc, char* argv[])
{
  std::string s("Hello world");
  f(s); // <- This is ok
  f(std::string("Hello world")); // <- This is incorrect (g++)
  return 0;
}

It compiles without errors on VC++ 8.0 (2005), while on gcc 4.1.2
(and later) it gives the following error:

g++ -O2 -g -Wall -fmessage-length=0 -c -o main.o main.cpp
main.cpp: In function 'int main(int, char**)':
main.cpp:11: error: invalid initialization of non-const reference of
 type 'std::string&' from a temporary of type 'std::string'
main.cpp:4: error: in passing argument 1 of 'void f(std::string&)'
make: *** [main.o] Error 1

What I know is that temporaries can be passed as const references
and that VC allows passing them as non-const references as an
extension to the standard.
What I don't know precisely is whether there is any potential risk
of error in doing as above.

Could you help me understand the rationale of the two approaches?

Thanks in advance,
eca

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