source: tests/concurrency/channels/hot_potato.cfa @ e8b5ba4

#include <locks.hfa>
#include <fstream.hfa>
#include <stdio.h>
#include <channel.hfa>
#include <thread.hfa>
#include <time.hfa>
#include <string.h>

size_t total_operations = 0;
ssize_t Processors = 1, Tasks = 4;                                              // must be signed

owner_lock o;

typedef channel( int ) Channel;

Channel * chain;

bool done = false;
int id_counter = 0;
thread Task { int id; int right; };
static inline void ?{}( Task & this ) with(this) {
    id = __atomic_fetch_add( &id_counter, 1, __ATOMIC_SEQ_CST );
    right = (id + 1) % Tasks;
}
void main(Task & this) with(this) {
    size_t runs = 0;
    try {
        for ( ;; ) {
            if ( done ) break;
            remove( chain[id] );
            insert( chain[right], 0 );
            runs++;
        }
    } catch ( channel_closed * e ) {}
    lock( o );
    total_operations += runs;
    unlock( o );
}

int main( int argc, char * argv[] ) {
    switch ( argc ) {
          case 3:
                if ( strcmp( argv[2], "d" ) != 0 ) {                    // default ?
                        Tasks = ato( argv[2] );
            if ( Tasks < 1 ) fallthru default;
                } // if
          case 2:
                if ( strcmp( argv[1], "d" ) != 0 ) {                    // default ?
                        Processors = ato( argv[1] );
                        if ( Processors < 1 ) fallthru default;
                } // if
          case 1:                                                                                       // use defaults
                break;
          default:
                exit | "Usage: " | argv[0]
             | " [ processors (> 0) | 'd' (default " | Processors
                         | ") ] [ channel size (>= 0) | 'd' (default " | Tasks
                         | ") ]" ;
        } // switch

    processor proc[Processors - 1];

    sout | "start";

    chain = aalloc( Tasks );
    for ( i; Tasks ) {
        chain[i]{ 1 };
    }

    insert( chain[0], 0 );
    {
        Task t[Tasks];
        sleep(10`s);
        done = true;
        for ( j; Tasks )
            close( chain[j] );
    }
    
    // sout | total_operations;

    sout | "done";

    adelete(chain);

    return 0;
}