回答編集履歴
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追記
test
CHANGED
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@@ -1,3 +1,60 @@
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pthread_mutex 使って排他すればいい。
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https://qiita.com/ryo_manba/items/e48faf2ba84f9e5d31c8
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```C
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#include <stdio.h>
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#include <pthread.h>
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const size_t loop_max = 10000;
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int sum = 0;
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pthread_mutex_t mtx;
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void f1() {
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size_t i;
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printf("start thread1\n");
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for(i=0; i<loop_max; i++){
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pthread_mutex_lock(&mtx);
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sum += 2;
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pthread_mutex_unlock(&mtx);
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}
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printf("finish thread1\n");
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}
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void f2() {
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size_t i;
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printf("start thread2\n");
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for(i=0; i<loop_max; i++){
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pthread_mutex_lock(&mtx);
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sum += 3;
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pthread_mutex_unlock(&mtx);
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}
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printf("finish thread2\n");
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}
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int main() {
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pthread_t thread1, thread2;
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pthread_mutex_init(&mtx, NULL);
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pthread_create(&thread1,NULL,(void *)f1,NULL);
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pthread_create(&thread2,NULL,(void *)f2,NULL);
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pthread_join(thread1,NULL);
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pthread_join(thread2,NULL);
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pthread_mutex_destroy(&mtx);
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printf("done\n");
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printf("sum=%d\n", sum);
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return 0;
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}
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```
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実行結果:
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```
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start thread1
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start thread2
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finish thread1
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finish thread2
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done
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sum=50000
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```
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60
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