It's not too hard a process, but it does take some manual troubleshooting to get it to work -- and even then I don't guarantee that 100% of the commands will work exactly as they do in the 32-bit version.
1) First, download a fresh version of QB64.
2) Download a fresh version of mingw -- the 64-bit compiler which you want to use. (Some of the older versions work perfectly well, but I don't know which one. If you have time, patience, and bandwidth, you might download archived versions and find one that plugs in perfectly well and which won't need any modification. I'd start by looking for a copy 2-3 years old, if I wanted to go that route.)
3) Go into your QB64 folder and remove the old version of the c-compiler. Paste the new version in and extract it into that folder. Look for the file called "INSTALL_MINGW_HERE.txt". When you see it, you're in the proper folder.
Only Windows users need these files.
This is a copy of the "Mingw-w32 (i686) ToolChain" from "http://www.drangon.org/mingw/"
After extraction, the 7 (or so) folders should be manually placed directly into this folder named
"internal\c\c_compiler\"
If you don't have a folder called "internal\c\c_compiler\bin" after extraction you have
done something wrong. There should be about 6 other folders here too.
Due to the large size of the Windows C++ compiler it was not practical to distribute it uncompressed,
expecially under a source revision system.
4) Run the "setup_win.bat" in the main QB64 folder. If all works well, CONGRATULATIONS!! You now have a 64-bit version of QB64. You downloaded an older version of mingw x64 which is error free and works as it should with QB64. Sing a happy song, try everything out, and you shouldn't have any issues.
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IF, however, the setup batch file fails to work properly, you'll have to look close at the error messages and go in and do some manual editing of a few lines inside the CPP files which mingw uses...
From what I remember, it's a simple patch, with only a few lines needing to be altered for variable declarations.
lotr and
rotr are the two variables which aren't declared in scope, (if I remember correctly), and the setup script will point you towards the file which contains the error.
All you need to do is go in, remark out a few lines. It has a few #ifdef blocks which sets different values for those commands, and whatever the heck they're doing, they're doing it wrong. Inside the file, you should be able to see that alternative definition -- just remark those lines out or remove them and save that file.
Run setup.bat a second time and you should get a 64-bit version of QB64.exe this time around -- with one cavet: I don't guarantee that every command will work as they should. _MEM commands, in particular, seem completely screwy in the 64-bit version which needs modification... So does a few more things, but I don't remember what they were. 99% of all commands work perfectly fine. 1% work, but work WRONG. As long as you stay away from those particular commands (once you sort out what they are), you can write 64-bit programs in basic for windows.
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Honestly, the BEST solution (since no one is supporting 64-bit windows versions), is to download an archived version of the x64 mingw compiler and use it. Up until 2 or 3 years ago, all you had to do is plug it in, rebuild QB64, and things worked just fine. Then mingw did several updates and it no longer worked as advertised for QB64...
The 32-bit compiler that comes packaged with QB64 is the same one that's been with it for years. I don't even know if someone could just swap in the newest version of the 32-bit mingw and have it work, without needing to modify and tweak things first. Who knows which commands were obsoleted, altered, removed, or replaced with newer functions??
Find the older version of the 64-bit compiler and you're golden. Get a newer version and you'll have to manually troubleshoot things yourself to make certain they all work properly.
I'm sorry I don't remember what the last plug-in-and-go version was, which worked without needing any alterations. If anyone takes time to test them out and finds out for us, let us know. Maybe somebody here will host the proper version and then there'll never be any issues for anybody who wants a 64-bit version from now on.