I was developing an application using xcode 4 to target snow leopard (10.6)
Now, nearly the end of the development, I've been asked to support 10.5+.
I have set the Mac OS deployment target to 10.5 and compiled.
The compiler (LLVM 2.0) and linker seems to be happy with the change
but I came across a feature I've used from NSWindow (isOnActiveSpace) which is states as AVAILABLE_MAC_OS_X_VERSION_10_6_AND_LATER
This I understand states that it won't work (throw exception?) in 10.5 but no warning were raised when building.
I currently don't have a leopard installation and it will take our QA some time to arrange a computer for that, so in your experience, what should I do next? how can I go over the code and make sure that all the APIs I've used are in fact safe for 10.5?
Set MAC_OS_X_VERSION_MAX_ALLOWED to 1050 and see what symbols disappear. More info in TN2064.
Related
I am developing an app using Xcode 4.6 on an OS X 10.8 machine. The app deployment target is set to 10.6, which is what we need to support. But when I archive the app (compile, link and embed resources+frameworks) and deploy (aka copy) it to the 10.6 test machine, it crashes with a generic Segmentation fault. It works fine on 10.7.
I can't compile the project in Xcode on the older Mac because the app is built using the newer compiler (it uses ARC, implicit property synthesis, the new objective-c literal syntax, etc.). It also wouldn't type check because the base SDK is 10.8 and it references some 10.8 tokens which the compiler on the 10.6 machine doesn't know about.
Any suggestions on how to go about debugging the app?
I'm not affiliated with this company/software in any way, but Deploymate is a paid app which can scan your app for SDK usage and tell you when you are calling selectors and APIs that are unavailable on older OS versions. This can help you track down exceptions and crashes relating to API usage.
You are very likely using one or more 10.7+ APIs that crash on 10.6. With a 10.8 target SDK you allow all the calls to function that are available in that SDK. However apps are bound late so this doesn't crash when you do not actually call those functions. You need an explicit check similar to this (here for the full screen feature):
#if MAC_OS_X_VERSION_MAX_ALLOWED > MAC_OS_X_VERSION_10_6
if (runningOnLionOrLater) {
[mainWindow setCollectionBehavior: NSWindowCollectionBehaviorFullScreenPrimary];
[toggleFullscreenItem setHidden: NO];
}
#endif
One way to determine the current version is:
int macVersion;
if (Gestalt(gestaltSystemVersion, &macVersion) == noErr) {
runningOnLionOrLater = macVersion > MAC_OS_X_VERSION_10_6;
}
For debugging the problematic calls simply set the base SDK to 10.6 and XCode should mark those functions that are not available there.
While there is no real good solution to this (I've seen simply different behaviors on different macOS versions) and no way to simply simulate an older macOS version, if you have a machine to spare:
It is possible to use an external HD, partition it and install different macOS versions. They all can be bootable and it's a matter (pain) of restarting the machine for every OS version.
after reading the apple SDK guide
https://developer.apple.com/library/mac/#documentation/developertools/conceptual/cross_development/Overview/overview.html
I'm still confused of how to make the mac app backward compatible & how to test them properly
I have an app, I run it and tested it on Mountain Lion 10.8 without any problem, however I want to make this app backward compatible so that other users can run it on a mac 10.6 - 10.7 machine.
I have an apple developer id and I can download the old versions of 10.7 and 10.6, but the problem is, I have a 2011 macbook air which is currently running 10.8, and that's the only apple machine that I have. Can I test the 10.7 and 10.6 by using vmware or parallels?
in my project settings, I set the target deployment to 10.6 (as I want 10.6 users to run my app), but should I set my SDK to 10.8 or 10.7? if I set the SDK to 10.8 but having the target deployment set to 10.6, if I fix all the xcode warnings will it run successfully on 10.6??
from the SDK drop down, I can only set to 10.8 or 10.7, but 10.6 is missing, how do I fix that?
thanks in advance
I develop on a 10.8 box and support back to 10.5. Just a couple of months ago we dropped 10.4 PPC support, and I'm still cleaning out some of the 10.2-specific code. This may get a little rant-y, but I've been doing old versions for a long time. I have some opinions on the matter.
No matter what Apple says in their docs, if you want to support 10.6, then build with the 10.6 SDK. Do not rely on distribution target.
I have had this discussion with the Xcode engineers, and while they hold to Apple's party line that you should always build with the latest SDK, they also acknowledge that it's generally insane to do so. If you build against the 10.8 SDK and mark your deployment target at 10.6, you will get no warnings for using methods that do not exist on 10.6. The only way you will discover that you've used a nonexistent method is that it might give you strange bugs when run on 10.6. That's insane.
Remember, OS X doesn't crash when you send an unknown selector. It just aborts the current runloop. So the bugs are even harder to track down then on iOS, where it crashes the app.
Sure, you can do weak linking. Talk about dangerous.... Yes, there are a few times this is useful, but the compiler gives you no warning if you don't do it correctly. If I'm going to do weak linking like this, I go the other way, linking against the old SDK and copying the new function's prototype into my implementation. That way I have documentation of every function I think I'm going to weak-link.
Download the old SDKs and symlink them into your Xcode distribution.
Guard them jealously. Apple will try to delete them every time you upgrade Xcode. Make your own copies and stick them in /SDKs or somewhere else away from Xcode. I provide a script called fix-xcode to manage the symlinks automatically. Am I bitter at Apple for their relentless insistance on deleting my old SDKs? Yes, I am.
You can run 10.6 Server in a VM legally. You can run 10.7+ Desktop in a VM legally. These are good ways to test your code.
Or you can do what I do and have a small pile of old MacBooks each with two or three partitions on them that you reboot all the time.
Now that 10.7 comes from App Store, it's a little harder to make VMs. My strong recommendation is to snapshot your image immediately after install, and make a clean backup copy of it. You'll want to be able to clone that image from time to time when you need to get back to a "raw" machine.
Get in the habit of squirreling away SDKs as they come out. 10.8 will be old some day. You might as well make a copy now while it's easy.
Whether you support individual dot-releases or not, it can be very helpful to keep around the upgrade packages for individual dot releases. When you encounter customers running non-current releases, it's nice to be able to check whether an "unreproducible" bug in fact is easily reproducible on their specific version. Whether this is worth it or not depends heavily on your product and customers. It was a life-saver for me when 10.4.11 made major changes to WebKit during a dot release...
Invest in a small NAS or a big external USB drive (though I've had trouble with those failing when used extensively, so I prefer a RAID). You'll need the space. You want to hold onto lots of VMs and lots of SDKs and sometimes even old versions of Xcode.
Adding to Rob Napier's great in-depth answer:
To use an old SDK, put the SDK (or a symlink) to it here:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs
With XCode 7.3 or later, you need you to open this file and change "MinimumSDKVersion" (otherwise XCode will refuse to use the old SDK):
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Info.plist
You can install multiple versions of Mac OS on a single machine, booting between each.
The SDK should be the latest (10.8).
See 2.
One alternative to 1 that I've considered (I am in the same boat) is to create a Snow Leopard Hackintosh using an old PC and just installing Lion and Mountain Lion on my MBP.
You need to do these settings :
1.Set the Base SDK to Current version of Mac (ex. 10.7)
2.Set the Deployment SDK to older version (ex.1.4)
I have developed a Cocoa App on Lion and now I would like to add compatibility with Leopard and Snow Leopard.
I tried to set the development target to 10.5 but it still has crash problems on Leopard and Snow Leopard.
I tried also to open the project with old versions of Xcode, but I get hundreds of compile errors (I guess it's because I can't compile the program with the old Mac OS SDK)
Do you have any advice about solving the retro-compatibility problems of Cocoa Apps?
I think it's generally not a very good idea to develop for the latest OS then try to support older OSes at the last minute. If you've used any APIs that were introduced in an OS later than the oldest you're trying to support, you'll have to rewrite code to avoid using those APIs. It's generally not worth the trouble.
That said, there's no secret to supporting older OSes. You just need to make sure that you only use APIs (classes, methods, functions) that are available on the oldest OS you're trying to support. You'll notice when looking at the documentation that for each method, under "Availability", it will tell you which versions of the OS include that method. Something like:
Availability
Available in Mac OS X v10.6 and later.
Assuming you don't use any APIs not available on an OS version you're targeting, all you need to do is set the deployment target to the lowest OS you're targeting, and build. You will of course also want to test thoroughly on each OS version you're supporting.
Your question would be easier to answer in more detail if you elaborated on the "crash problems" you're seeing on Leopard and Snow Leopard.
First, install the 10.5 SDK on your Mac. This may not be necessary, but do it anyway. You can find instructions on the Internet. Keep in mind that compiling with the 10.5 SDK will ensure compatibility, but you won't be able to use newer OS X features unless you load them dynamically.
Second, go into your .xib files and on the File Properties tab (first notch in the Inspector pane) disable auto layout and set the deployment target to 10.5.
I am new here and new in Xcode world.
I made a simple app with Xcode 3.2 on Snow Leopard.
The resulting built app works on snow leopard, however it will not even start on leopard (10.5.8) - I get message "You cannot use this version of application with this version of Mac OS X". Is it normal?
Or is there a way to make app that will work both on Snow Leopard and Leopard? Please advise, as I have no way to find out myself
Thanks for any input
You need to change the deployment target in your Build Settings. You should set it to the lowest version of OS X that you're willing to provide support for. You should set your base SDK to the latest available public SDK.
If you do this, you must ensure that you only use new 10.6-only APIs after doing runtime checks for their existence. To do this, you can use functions like NSClassFromString and respondsToSelector:.
Any Frameworks or libraries that are new to 10.6 should be weak-linked. This will prevent the app from trying to load those frameworks on 10.5 and thus cause the program to crash when it doesn't find the frameworks.
All explained in the SDK Compatibility Guide from Apple (Requires (free) login).
I've been building a basic Cocoa application with Core Data and Interface Builder, and no extra coding, frameworks, or header files. I sent it to someone to test on their machine (a last-gen G5 iMac), and they got a message saying that their machine couldn't run it. I discovered the switch to compile for PPC, so I built a PPC version of the application to try out, and that produced the following error message:
You cannot use this version of Application on this version of Mac OS X.
I'm running Xcode 3.2.1, Interface Builder 3.2.1, and OS 10.6.2. The conversation with my tester was a bit confusing; at first it sounded like she only had Tiger on her machine, saying Leopard was incompatible (I corrected and said that Leopard should be, it's Snow Leopard that isn't), and then by the end of the conversation she was about certain that her machine was running Leopard, but had already shut it off by then. So I'm not sure which version of OS X is on the offending iMac, but it's the latest version of either 10.4.11 or 10.5.8 (the tester is in a remote location, so I can't verify personally at the moment).
What can I tweak to try and improve compatibility on my tester's machine?
If they're seeing that message, it's most likely because your app has the LSMinimumSystemVersion key (Minimum system version) set in the Info.plist. You should take this key out or set it to the actual the minimum OS X version you support.
Once you do this, you may well run into the next problem. (Probably a dynamic linker error as a result of using a framework or API that didn't yet exist on 10.4 or 10.5.)
The main problem here is that you're sending it out to a system where you haven't actually tried it. If you plan to support 10.4, 10.5, or both, I highly recommend that you find a spare hard drive, partition it up, and install 10.4.11 and 10.5.8. There are many issues that will crop up on older OS's and if you haven't tried it yourself, it's unlikely it will work smoothly on the first try.