55 lines
1.0 KiB
C++
55 lines
1.0 KiB
C++
#include <pthread.h>
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#include <stdio.h>
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#include <unistd.h>
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pthread_mutex_t mutex;
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int count;
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void increment(int ntimes )
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{
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for ( int i = 0; i < ntimes; i++ ) {
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pthread_mutex_lock(&mutex);
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int c;
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c = count;
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c = c + 1;
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count = c;
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pthread_mutex_unlock(&mutex);
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}
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}
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int main( int argc, char ** argv )
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{
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int n = 10000000;
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pthread_t t1, t2;
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pthread_attr_t attr;
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pthread_mutex_init(&mutex, NULL);
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pthread_attr_init( &attr );
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pthread_attr_setscope(&attr, PTHREAD_SCOPE_SYSTEM);
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printf("Start Test. Final count should be %d\n", 2 * n );
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// Create threads
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pthread_create( &t1, &attr, (void * (*)(void *)) increment,
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(void *) n);
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pthread_create( &t2, &attr, (void * (*)(void *)) increment,
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(void *) n);
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// Wait until threads are done
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pthread_join( t1, NULL );
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pthread_join( t2, NULL );
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if ( count != 2 * n ) {
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printf("\n****** Error. Final count is %d\n", count );
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printf("****** It should be %d\n", 2 * n );
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}
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else {
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printf("\n>>>>>> O.K. Final count is %d\n", count );
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}
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}
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