I know exactly what boundaries are lacking, that is what led to my original comment. And yes, functions can do whatever they want. Programmers expect special language features to be more useful than the alternatives though! If a function does call abort(), I can actually see the call, along with a stack trace; with source code I even know why the code exited. Odds are good that the abort() came from an assert() macro, giving me control over which builds can unexpectedly exit. Exceptions give me none of that, and introduce ways for valuable state to be totally lost in the process.
A function could just not use exceptions at all and just call abort() on error, what are you going to do then?
There isn't really a concept of library boundary in C++; you just have compilation units at best. At worst, you have a library that's implemented entirely as headers. What happens when the exception originates in your code but goes through the libraries call stack (because it was a call on a passed-in object or callback)? What you are asking for is likely impossible.