Fixing "Use of undeclared identifier 'NSPreferencePanesDirectory'" - objective-c

Question

My application uses the following code:
#if MAC_OS_X_VERSION_10_5 < MAC_OS_X_VERSION_MAX_ALLOWED
NSArray *globalPreferencePanes =
NSSearchPathForDirectoriesInDomains(NSPreferencePanesDirectory,
NSAllDomainsMask, YES);
#else
NSArray *globalPreferencePanes =
[NSArray arrayWithObjects:#"/Library/PreferencePanes",
[#"~/Library/PreferencePanes" stringByExpandingTildeInPath], nil];
#endif
return globalPreferencePanes;
The project under which I'm compiling this is aimed at the 10.5 Mac OSX SDK, where NSPreferencePanesDirectory does not exist (it only exists in 10.6+). Because of this, I have the #if and #else in order to check what version of Mac OSX we're running under, so I know whether I should use the NSPreferencePanesDirectory or just manually give the location of the preference pane directories.
What should I change in order to stop getting this "use of undeclared identifier" error?
Thanks.

Answer 1

#if is evaluated at compile time, not run time. What you probably want to do is use the current SDK (10.7), and do something like this:
NSArray *globalPreferencePanes;
if (NSAppKitVersionNumber >= NSAppKitVersionNumber10_6)
globalPreferencePanes = NSSearchPathForDirectoriesInDomains(NSPreferencePanesDirectory, NSAllDomainsMask, YES);
else
globalPreferencePanes = [NSArray arrayWithObjects:#"/Library/PreferencePanes", [#"~/Library/PreferencePanes" stringByExpandingTildeInPath], nil];
return globalPreferencePanes;
Making sure to set your target OS version to 10.5 so the symbol is weak linked. Otherwise, you could drop down and use CoreServices' FSFindFolder():
NSMutableArray *globalPreferencePanes = [NSMutableArray array];
FSRef foundRef;
OSErr err = FSFindFolder(kLocalDomain, kPreferencePanesFolderType, false, &foundRef);
if (err != noErr) {
CFURLRef url = CFURLCreateFromFSRef(NULL, &fsRef);
CFStringRef path = CFURLCopyPath(url);
[globalPreferencePanes addObject:(id)path];
CFRelease(path);
CFRelease(url);
}
OSErr err = FSFindFolder(kUserDomain, kPreferencePanesFolderType, false, &foundRef);
if (err != noErr) {
CFURLRef url = CFURLCreateFromFSRef(NULL, &fsRef);
CFStringRef path = CFURLCopyPath(url);
[globalPreferencePanes addObject:(id)path];
CFRelease(path);
CFRelease(url);
}
return globalPreferencePanes;
(Not tested)

Answer 2

If you are using 10.5.x you will still get an error since "NSPreferencePanesDirectory" is not a known symbol. I solved this issue for a friend and changed the FindPrefsDir function code in osxsupport.m to:
char *FindPrefsDir(void)
{
char *resstr = NULL;
NSArray *globalPreferencePanes;
globalPreferencePanes = [NSArray arrayWithObjects:#"/Library/PreferencePanes", [#"~/Library/PreferencePanes" stringByExpandingTildeInPath], nil];
if ([globalPreferencePanes count] > 0)
{
resstr = StringToChar([globalPreferencePanes objectAtIndex:0]) ;
}
return resstr;
}
Thanks to Wevah for his code suggestion, but it didn't directly work for me. So I changed it a little bit and my friend who is still on 10.5.x could perfectly build it after that.