Function breakpoint 

pub fn breakpoint()

🔬This is a nightly-only experimental API. (breakpoint #133724)

Compiles to a target-specific software breakpoint instruction or equivalent.

This will typically abort the program. It may result in a core dump, and/or the system logging debug information. Additional target-specific capabilities may be possible depending on debuggers or other tooling; in particular, a debugger may be able to resume execution.

If possible, this will produce an instruction sequence that allows a debugger to resume after the breakpoint, rather than resuming at the breakpoint; however, the exact behavior is target-specific and debugger-specific, and not guaranteed.

If the target platform does not have any kind of debug breakpoint instruction, this may compile to a trapping instruction (e.g. an undefined instruction) instead, or to some other form of target-specific abort that may or may not support convenient resumption.

The precise behavior is not guaranteed, it depends on the architecture and operating system. Not all architectures guarantee that a breakpoint instruction interrupts execution in the absence of a debugger, and not all operating systems and execution environments guarantee that such an interrupt aborts the current process. On operating systems where the behavior of the interrupt can be overwritten by the application (e.g. via a SIGTRAP signal handler), the application should make sure to still abort the process. However, code not fully in control of that application state (e.g. signal handlers) cannot always rely on that for soundness. If you do rely on this, such that your code’s soundness requires applications to not continue from your breakpoints, please document that for your users.

The precise instruction is guaranteed only on the following targets:

• On x86 targets, this produces an int3 instruction.
• On aarch64 targets, this produces a brk #0xf000 instruction.