Re: how to detect OS architecture?

[Gary Willoughby]

On Monday, 16 December 2013 at 13:19:52 UTC, Hugo Florentino 
wrote:
On Mon, 16 Dec 2013 12:59:52 +0100, John Colvin wrote:
On Monday, 16 December 2013 at 11:56:07 UTC, Hugo Florentino 
wrote:
On Mon, 16 Dec 2013 12:40:17 +0100, MrSmith wrote:
I think this is what he want
http://dlang.org/phobos/core_cpuid.html#.isX86_64

Thanks, that's precisely what I needed :)

Are you sure?

This will tell you about the processor, but not necessarily 
about
what the OS supports. I don't know, but you may find that when 
using
windows 32bit on an x64 machine, cpuid will tell you the cpu 
is 64bit,
but the OS won't let you run any 64bit code.

You are right. I realized that this function was not quite what 
I needed when running this code on a 32 bit system:

import std.stdio, core.cpuid;

int main() {
  immutable auto appname = "myapp";
  auto appversion = !isX86_64() ? appname ~ "32" : appname ~ 
"64") ~ ".exe";
  scope(failure) return -1;
  writeln(appversion);
  return 0;
}

I was expecting "myapp32.exe" but got "myapp64.exe". Apparently 
what isX86_64() detects is the capability of the processor, not 
the arquitecture of the OS.

So currently D has no specific function for detecting the OS 
architecture at runtime? I had not expected this.

I will try using the other options though. Thanks

Try building the launcher as a 32bit executable then use the 
following code:

import std.stdio;
import core.sys.windows.windows;

enum AMD64   = 9;
enum IA64    = 6;
enum X86     = 0;
enum UNKNOWN = 0xFFFF;

void main()
{
        SYSTEM_INFO executableEnvironment;
        SYSTEM_INFO outerEnvironment;

        GetSystemInfo(&executableEnvironment);
        GetNativeSystemInfo(&outerEnvironment);

        // See the above enums for values.
	writefln("Executable: %s", 
executableEnvironment.wProcessorArchitecture);
        writefln("Outer: %s", outerEnvironment.wProcessorArchitecture);
}

If the launcher is running under Wow64 (the 32bit emulation layer 
on a 64bit processor) the results will be different for 
executableEnvironment and outerEnvironment. GetSystemInfo gets 
the environment the executable is running under, 
GetNativeSystemInfo gets the 'real' environment. I guess it's a 
place to start?