Base SDK Deployment Target - hewigovens/hewigovens.github.com GitHub Wiki

SDK Time example

Notes:

The libraries in an iOS or OS X SDK are stubs for linking only; they do not contain executable code but just the exported symbols. SDK support works only with native build targets.
The effects of these settings at compile time and run time are as follows. If your code uses a symbol:
- Not defined in the base SDK (for example, a symbol from a newer OS), you get a compile-time error.
- Defined in the base SDK but marked as deprecated, you get a compile-time warning. Configuring a Project for SDK-Based Development Base SDK and Deployment Target Settings
Defined in the deployment target, your code links and builds normally. At run time:
- On a system running an OS earlier than the deployment target, your code may fail to load if you use symbols unavailable in that OS.
- On a system running an OS equal to or later than the deployment target, your code has null pointers for symbols not available in that OS. Prepare your code for Weakly Linking
If a weakly linked symbol present in a code module is not present in the framework, the code module can continue to run aslong asit does not reference the symbol. If a weakly linked symbol is present in its framework, the code can use it normally.
- extern int MyWeakLinkedFunction() __attribute__((weak_import));
- -weak_framework <framework_name>