Listing 32 illustrates a n example comparable to the Win32 code in List ing 3 1 earlier Just as we had used the Wa i t F o r S i n g l eOb j ect Win32 API to wait for the thread to exit, we use Th read's J o i n method We'll review J o i n i n more detail later, though i t doesn't get much more complicated than what is shown here You'll notice that the CLR doesn't expose any sort of thread exit code capability

L I STI N G 3 2 : Creati n g a new OS thread with the N ET Fra mework's Thread class u s ing System; using System Threa d i n g ; c l a s s Program { p u b l i c stat i c void M a i n ( ) { Thread newThread new Th read ( new Pa ramet e r i zedThreadSt a rt ( MyThreadSt a rt ; Console Wr i t e L i n e ( " { 0 } : C reated t h read ( 10 { l } ) " , T h read C u rrentThread ManagedThrea d I d , newT h read Ma nagedThread I d ) ; newTh read St a rt ( " He l l o wo rld " ) ; I I Begin execution newThread J oi n ( ) ; II Wait for t h e t h read to f i n i s h Console Wr i t e L i n e ( " { 0 } : Th read exited " , T h read C u r r e ntTh read ManagedThread I d ) ; } p r ivate s t a t i c void MyT h readSt a rt ( ob j e c t obj ) { Console Writ e L i ne ( " { 0 } : R u n n i n g : { l } " , Th read C u rrentThread ManagedThrea d I d , obj ) ; }

T h read newT h read { Console Wr it e L i ne ( " { 0 } : R u n n i n g { l } " , T h read C u rrentThread ManagedThrea d I d , obj ) ; }); newT h read St a rt ( " He l l o wo rld (with anon delegates ) " ) ; newThread J oi n ( ) ;

new T h read ( delegat e ( ob j e c t obj )

Thread newTh read new Thread ( obj > Console WriteLine ( " { e } : R u n n i n g { l } " , Thread Cu r rentThrea d ManagedThrea d l d , obj ) )j n ewTh read St a rt ( " He l l o , world ( with lambd a s ) " ) j newTh read J oin ( ) j

We make use of the C u r rentTh r e a d static property on the T h r e a d class, which retrieves a reference to the currently executing thread, much like GetC u r rentTh r e a d in Win32 We then use the instance property Man agedTh r e a d l d to retrieve the unique identifier assigned by the CLR to this thread This identifier is completely different than the one assigned by the OS If you were to P I Invoke to GetC u r re ntTh r e a d l d , you'll likely see a different value

p u b l i c c l a s s Th read { p u b l i c s t a t i c Thread C u r rentTh read { get j } j p u b l i c int ManagedTh read l d { get j }

Again, this code snippet isn' t very illuminating We'll see more complex examples But as you can see, the idea of a thread as seen by Win32 and managed code programmers is basically the same That's good as it means most of what we've discussed and are about to discuss pertains to native and managed code alike

Thread Termination A thread goes through a complex lifetime, from runnable to running to pos sibly waiting, possibly being suspended, and so forth, but it will eventually terminate Termination might occur as a result of any one of a number of particular events

1 The thread start routine can return normally 2 An unhandled exception can escape the thread start routine, "crash ing" that thread