Apple has provided, with limited documentation, a new public framework called CoreWLAN.  It looks pretty easy to use.  To do a scan of the WIFI access points, you can simply do:

#import <Cocoa/Cocoa.h>
#import <CoreWLAN/CoreWLAN.h>

NSError *err = nil;
NSDictionary *params = nil;

NSArray* scan = [NSMutableArray arrayWithArray:[[CWInterface interface] scanForNetworksWithParameters:params error:&err]];

This is all fine and dandy.  However, Firefox uses 10.5, and so using the above code will not compile using the old SDK.  Unfortunately, Apple didn’t provide any C apis – only exposing this objective-C API.  So, what I had to do was some objective-c magic.  Check out the reference (http://developer.apple.com/mac/library/documentation/Cocoa/Reference/ObjCRuntimeRef/Reference/reference.html)

Basically, we needed to be able to dynamically load the CoreWLAN library, that is simple enough:

void *corewlan_library = dlopen(“/System/Library/Frameworks/CoreWLAN.framework/CoreWLAN”,  RTLD_LOCAL);

Now that this library has been loaded, we want to simulate the objective-c call “[CWInterface interface]“.

// get the class
Class CWI_class = objc_getClass(“CWInterface”);
// register the selector name
SEL interfaceSel = sel_registerName(“interface”);
// make the call
id interface = objc_msgSend(CWI_class, interfaceSel);

This mess above is the same as:

id interface = [CWInterface interface];

As you probably can see, it isn’t that hard to do this, just it is syntactically nasty.  Here is the source to the little application I was testing with:

#include <mach-o/dyld.h>
#include <dlfcn.h>
#include <unistd.h>

#include <objc/objc.h>
#include <objc/objc-runtime.h>

Class CWI_class = objc_getClass(“CWInterface”);
printf(“cwi class %x\n”, CWI_class);

SEL interfaceSel = sel_registerName(“interface”);
printf(“sel: %x\n”, interfaceSel);

SEL scanSel = sel_registerName(“scanForNetworksWithParameters:error:”);
printf(“scanSel: %x\n”, interfaceSel);

id interface = objc_msgSend(CWI_class, interfaceSel);
printf(“interface: %x\n”, interface);

id scanResult = objc_msgSend(interface, scanSel, 0, 0);
printf(“scanResult: %x\n”, scanResult);

Hope this helps.  Please let me know of an easier way, if one exists.