這是我的代碼。基本上,我有很多孩子,他們應該從ptList中計算出一定數量的點數,將相應的點數傳遞給父級,父級將這些點數加起來。不幸的是,對於我的printf,「addToTotal」變量沒有更新過第一個孩子,我的回答不正確。任何建議都會令人難以置信。通過來自多個孩子的管道寫入父進程
pid_t worker[ workers ];
for (int i = 0; i < workers; i++) {
//printf("I am child %i\n", i);
if ((worker[i] = fork()) < 0) {
fail("Can't create child");
} else if (worker[i] == 0) {
//Close the reading end of the pipe for each child
close(pfd[0]);
// Get each of the workers to compare points
for (int k = i; k < ptCount; k += workers) {
for (int j = k + 1; j < ptCount; j++) {
int dx = ptList[ k ].x - ptList[ j ].x;
int dy = ptList[ k ].y - ptList[ j ].y;
if (dx * dx + dy * dy <= dsq)
childTotal++;
}
}
printf("Child %i total: %i\n", i, childTotal);
lockf(pfd[ 1 ], F_LOCK, 0);
write(pfd[ 1 ], &childTotal, sizeof(childTotal));
lockf(pfd[ 1 ], F_ULOCK, 0);
close(pfd[ 1 ]);
exit(0);
wait(NULL);
}
wait(NULL);
close(pfd[ 1 ]);
read(pfd[ 0 ], &addToTotal, sizeof(addToTotal));
printf("AddToTotal: %i\n", addToTotal);
total += addToTotal;
}
在循環的第一次迭代中,父級關閉管道的寫入側。在第二次迭代中,子級繼承了寫入側關閉的管道。 –