Push not working in my app

Question

W released a Push Enabled app recently. Although several users have purchased the app, we are seeing NO TOKENs being sent to our servers. We are unclear on what is going on?
1. We built the app on the 3.0 SDK application for Device 2.0, but as we are supporting Push Notification, we have Push related API's inside #ifdef _IPHONE_30 macros. Will 3.0 API's inside #ifdef _IPHONE_30 macro be compiled and when installed on a 3.0 Device will these API's get executed? That was our expectation but again we are not seeing any tokens coming through.
2. We see apps out there similar to ours that support 2.0 and 3.0 in the same build, and have Push features on 3.0. We assume the way to do that is to build with #def macros as described in #1 above, and that is what we did. Is that wrong? Must an app supporting Push be exclusively built for 3.0 Device and can not support 2.0 devices?
Thanks in advance
Jay

Answer 1

Hi Jay - It might make more sense to review some basics instead of attempting direct answers to each of your questions.
Firstly, you can't use a compiler switch to determine which code blocks are selected at runtime. If a block of 3.0 code is switched in at compile time (i.e. added to the app), that block will be executed by all of the host devices. If the code isn't supported by lower iPhone OS versions, the app would crash on those systems (if allowed to load). On the other hand, if the 3.0 code is switched out at compile time, it's not added to the app and won't be executed by any of the host devices.
You may have been thinking of a runtime switch which detects the OS version and bypasses any incompatible code. There are ways of doing that on some platforms, but AFAIK such a build wouldn't work for an approved iPhone app because the app needs to be branded based on the lowest OS it supports. I.e., if I include 3.0-only features, the app will be marked 3.0 and OS 2.x will refuse to run it.
Although several users have purchased the app, we are seeing NO TOKENs being sent to our servers. We are unclear on what is going on?
It would appear that your #ifdef has switched out the code in question. If you're not sure whether a block of code is included in your app, I would recommend NSLog(). E.g.
#ifdef _IPHONE_30
NSLog(@"IPHONE30");
#endif
The above tells you if a compile time switch is turned on for the current build. I generally like to know what code was included in my app before it's out in the field.
We see apps out there similar to ours that support 2.0 and 3.0 in the same build, and have Push features on 3.0.
AFAIK, any build that has 3.0 features can't support 2.0, and any build that supports 2.0 can't include code that only runs on 3.0.
Each Xcode build is subject to two OS version settings:
1) The SDK version;
2) The Executable version.
Here's an article that explains these settings: [http://resources.pinchmedia.com/docs/pinchanalytics/iPhone_SDK_30_2xTargets].
For example, if you build for 2.1 using the 3.0 SDK, the compiler won't recognize API calls that are only available in 2.2 or 3.0, and the build will be marked 2.1 so any iPhone OS below 2.1 won't run it.
Hope that helps!
- Ray