With sigaction handlers (as opposed to the C standard library's simplistic signal handlers) it's not just exceptions, it's more general, like a condition system

With sigaction handlers (as opposed to the C standard library's simplistic signal handlers) it's not just exceptions, it's more general, like a condition system like in Common Lisp. From inside the handler you can analyze what's wrong, then manipulate the program state and then restart the computation where you were, or at the next instruction, or wherever else you choose. In contrast, your typical exception mechanism (as in Python or C++ or Java or whatever) will unwind the stack and make it impossible to restart from the exact place where the problem occurred.