runtime diagnostics

The following runtime diagnostics and logging options can be enabled in the scheme editor.

Runtime Sanitization options:

Option	Description
Address Sanitizer	Finds memory corruptions and other memory errors at runtime. Memory errors can lead to unpredictable behavior and can be hard to reproduce consistently. For details, read Address Sanitizer.
Thread Sanitizer	Detects data races at runtime. For example, when multiple threads access the same memory without synchronization and at least one access is a write. For details, read Thread Sanitizer.
Undefined Behavior Sanitizer	Detects undefined behavior at runtime. For example, any operation with unspecified semantics, such as dividing by zero, loading memory from a misaligned pointer, or dereferencing a null pointer. For details, read Undefined Behavior Sanitizer.

Note: Enabling Runtime Sanitization options requires recompilation the next time you Run your app for debugging.

Runtime API Checking:

Option	Description
Main Thread Checker	Detects invalid usage of AppKit, UIKit, and other APIs on a background thread. For details, read Main Thread Checker.

Memory Management options:

Option	Description
Malloc Scribble	Fills allocated memory with `0xAA` and deallocated memory with `0x55`.
Malloc Guard Edges	Adds guard pages before and after large allocations.
Guard Malloc	Uses `libgmalloc` to catch common memory problems such as buffer overruns and use-after-free.
Zombie Objects	Replaces deallocated objects with zombie objects. When you send a message to a zombie object, the runtime logs an error and crashes. You can look at the backtrace to see the chain of calls that triggered the zombie detector.

Logging options:

Option	Description
Malloc Stack	Records stack logs for memory allocations and deallocations.
Dynamic Linker API Usage	Logs dynamic-linker API calls (for example, `dlopen`).
Dynamic Library Loads	Logs dynamic-linker library loads.