Undefined reference using Allegro 5 with mingw-w64 - c++

Question

I'm trying to compile an Allegro 5 program on Windows 10 with mingw-w64.
I already had installed mingw-w64. Output from g++ --version is:
g++.exe (i686-posix-dwarf-rev2, Built by MinGW-W64 project) 7.1.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
I downloaded windows binaries for Allegro 5 from https://github.com/liballeg/allegro5/releases (File: allegro-x86_64-w64-mingw32-gcc-8.2.1-posix-seh-static-5.2.5.0.zip) and unzipped the file into C:/allegro5 so now I have C:/allegro5/bin, C:/allegro5/include, C:/allegro5/lib.
A small test program:
#include <stdio.h>
#include <allegro5/allegro.h>
int main(int argc, char **argv)
{
al_init();
return 0;
}
And finally the command I run to compile: g++ test.cpp -I"C:/allegro5/include" -L"C:/allegro5/lib" -lallegro (There is a lib file called liballegro.dll.a under C:/allegro5/lib)
But there are some problems while linking:
C:\Users\xxxx\AppData\Local\Temp\ccg5z97Y.o:test.cpp:(.text+0x1e): undefined reference to `al_install_system'
collect2.exe: error: ld returned 1 exit status
A) What may be the reason for this ?
B) What should I do to compile in a static way ? Is changing -lallegro to -lallegro-static enough ?

Answer 1

This:
g++.exe (i686-posix-dwarf-rev2, Built by MinGW-W64 project) 7.1.0
is one of the the 32-bit GCC variants provided by MinGW-W64. You are attempting to link the
32-bit code it generates with the 64-bit libraries provided in:
allegro-x86_64-w64-mingw32-gcc-8.2.1-posix-seh-static-5.2.5.0.zip
which will not work. Replace your compiler with the appropriate 64-bit variant x86_64-posix-seh