Multiple definitions of inline function C++ - c++

Question

I know there is already a lot of topics about this subject, however I didn't find in any of them the explanation to how it is possible to have one definition of an inline function per translation unit. I know that inline functions have external linkage, so when I call one inline function in different translation units they all reference the same function. I also know that in Linux the compiler registers inline function with the "W" symbol, so it is registered as a weak symbol (thanks to it the first definition encountered by the compiler of the inline function is the one considered). However whenever I use nm on the object files created by g++ in Windows there is no weak symbol attached to the function signature. How can the linker know which definition to consider and not to accuse of multiple definitions? (I don't show the linker's work but I tested it).
Here is some example code:
// main1.cpp
#include "main.hpp"
/* inline accepts one definition in each TU's */
inline void Test::hello_world()
{
std::cout << "Hello world" << std::endl;
}
/*void Test::hello_world()
{
std::cout << "Hello world" << std::endl;
}*/
extern void return_hello_world();
int main()
{
Test t;
t.hello_world();
return_hello_world();
return 0;
}
// main2.cpp
#include "main.hpp"
/* inline accepts one definition in each TU's */
inline void Test::hello_world()
{
std::cout << "Hello world" << std::endl;
}
/* void Test::hello_world()
{
std::cout << "Hello world" << std::endl;
} */
void return_hello_world()
{
Test t;
t.hello_world();
}
// main.hpp
#ifndef TEST
#define TEST
#include <iostream>
class Test
{
public:
void hello_world();
};
#endif
The results I receive are:
Windows:
Experimentation4> g++ -g -O0 -c main1.cpp main2.cpp
Experimentation4> nm main1.o
0000000000000000 b .bss
0000000000000000 d .ctors
0000000000000000 d .data
0000000000000000 N .debug_abbrev
0000000000000000 N .debug_aranges
0000000000000000 N .debug_frame
0000000000000000 N .debug_info
0000000000000000 N .debug_line
0000000000000000 N .debug_ranges
0000000000000000 N .debug_str
0000000000000000 p .pdata
0000000000000000 p .pdata$_ZN4Test11hello_worldEv
0000000000000000 r .rdata
0000000000000000 r .rdata$.refptr._ZSt4cout
0000000000000000 r .rdata$.refptr._ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_
0000000000000000 r .rdata$zzz
0000000000000000 R .refptr._ZSt4cout
0000000000000000 R .refptr._ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_
0000000000000000 t .text
0000000000000000 t .text$_ZN4Test11hello_worldEv
0000000000000000 r .xdata
0000000000000000 r .xdata$_ZN4Test11hello_worldEv
U __main
0000000000000029 t __tcf_0
0000000000000080 t _GLOBAL__sub_I_main
U _Z18return_hello_worldv
0000000000000044 t _Z41__static_initialization_and_destruction_0ii
0000000000000000 T _ZN4Test11hello_worldEv
U _ZNSolsEPFRSoS_E
U _ZNSt8ios_base4InitC1Ev
U _ZNSt8ios_base4InitD1Ev
U _ZSt4cout
U _ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_
0000000000000000 r _ZStL19piecewise_construct
0000000000000000 b _ZStL8__ioinit
U _ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc
U atexit
0000000000000000 T main
Linux:
Experimentation2$ g++ -O0 -g -c main1.cpp main2.cpp
Experimentation2$ nm main1.o
U __cxa_atexit
U __dso_handle
0000000000000081 t _GLOBAL__sub_I_main
0000000000000000 T main
U __stack_chk_fail
U _Z18return_hello_worldv
0000000000000043 t _Z41__static_initialization_and_destruction_0ii
0000000000000000 W _ZN4Test11hello_worldEv
U _ZNSolsEPFRSoS_E
U _ZNSt8ios_base4InitC1Ev
U _ZNSt8ios_base4InitD1Ev
U _ZSt4cout
U _ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_
0000000000000000 b _ZStL8__ioinit
U _ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc