source: doc/papers/concurrency/examples/RWMonitorEXT.cfa @ 2aab69b

arm-ehjacob/cs343-translationjenkins-sandboxnew-astnew-ast-unique-expr
Last change on this file since 2aab69b was 2aab69b, checked in by Peter A. Buhr <pabuhr@…>, 22 months ago

files added to concurrency paper

  • Property mode set to 100644
File size: 1.7 KB
Line 
1#include <fstream.hfa>
2#include <thread.hfa>
3
4volatile int SharedRW = 0;                                                              // shared variable to test readers and writers
5
6monitor ReadersWriter {
7        int rcnt, wcnt;                                                                         // number of readers/writer using resource
8};
9
10void ?{}( ReadersWriter & rw ) with(rw) { rcnt = wcnt = 0; }
11void EndRead( ReadersWriter & mutex rw ) with(rw) { rcnt -= 1; }
12void EndWrite( ReadersWriter & mutex rw ) with(rw) { wcnt = 0; }
13void StartRead( ReadersWriter & mutex rw ) with(rw) {
14        if ( wcnt > 0 ) waitfor( EndWrite : rw );
15        rcnt += 1;
16}
17void StartWrite( ReadersWriter & mutex rw ) with(rw) {
18        if ( wcnt > 0 ) waitfor( EndWrite : rw );
19        else while ( rcnt > 0 ) waitfor( EndRead : rw );
20        wcnt = 1;
21}
22int readers( ReadersWriter & rw ) { return rw.rcnt; }
23
24void Read( ReadersWriter & rw ) {
25        StartRead( rw );
26        sout | "Reader:" | active_thread() | ", shared:" | SharedRW | " with:" | readers( rw ) | " readers";
27        yield( 3 );
28        EndRead( rw );
29}
30void Write( ReadersWriter & rw ) {
31        StartWrite( rw );
32
33        SharedRW += 1;
34        sout | "Writer:" | active_thread() | ",  wrote:" | SharedRW;
35        yield( 1 );
36        EndWrite( rw );
37}
38
39thread Worker {
40        ReadersWriter &rw;
41};
42void ?{}( Worker & w, ReadersWriter * rw ) { &w.rw = rw; }
43void main( Worker & w ) with(w) {
44        for ( 10 ) {
45                if ( rand() % 100 < 70 ) {                                      // decide to be a reader or writer
46                        Read( rw );
47                } else {
48                        Write( rw );
49                } // if
50        } // for
51}
52
53int main() {
54        enum { MaxTask = 5 };
55        ReadersWriter rw;
56        Worker *workers[MaxTask];
57
58        for ( i; MaxTask ) workers[i] = new( &rw );
59        for ( i; MaxTask ) delete( workers[i] );
60        sout | "successful completion";
61} // main
62
63// Local Variables: //
64// tab-width: 4 //
65// compile-command: "cfa -O2 RWMonitorEXT.cfa" //
66// End: //
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