V

U

unary operators

list of, 21

overview, 21

unboxing, 278

unhandled exceptions

AppDomain.UnhandledException, 349–350

Application.ThreadException, 348–349

Exception Assistant, 351

overview, 347–348

trapping, 347

UnhandledExceptionEventHandler, 350

Unicode characters, 18

unmanaged callbacks, 621–622

unmanaged resources

boxing, 559

garbage collection overview, 555–559

generations, 555

handles, 596–597

managing, 595–597

memory pressure, 596

overview, 554–555

UnmanagedType enumeration, 623

unsafe code

appropriate uses, 601

blittable types, 611, 618

CharSet, 617

directional attributes, 620

DllImport, 612–616

explicit marshaling, 622–624

fixed-size buffers, 624–625

fixed statement, 609–610

formatted types, 618–620

Interop marshaler, 611

LayoutKind enumeration, 618

MarshalAs attribute, 624

nonblittable types, 611–612, 618

overview, 598–599, 601–603, 625

Platform invocation services. See Platform invocation services (PInvoke)

pointer parameters and return, 608–611

pointers, 604–607

Runtime Callable Wrapper (RCW), 602

stackalloc command, 610–611

StringBuilder class, 620–621

summary, 625

unmanaged callbacks, 621–622

void pointers, 605

unsafe keyword, 603

untrusted code. See unsafe code

URLs. See Web sites

user-defined types

operator overloading, 627

reference type constraints, 254

Userstring heap, 358