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#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <pthread.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#define MILLISECOND (1e6)
enum pipe_ends {
R,
W,
};
static void *work(void *);
int
main(void)
{
static const char msg[] = u8"Olá Mundo!\n";
int fds[2];
if (pipe(fds) == -1)
err(1, "pipe");
if (write(fds[W], msg, sizeof(msg) - 1) == -1)
err(1, "write[1]");
pthread_t thrd;
if ((errno = pthread_create(&thrd, NULL, work, (void *)fds)) != 0)
err(1, "pthread_create");
struct timespec ts = {.tv_nsec = 500 * MILLISECOND};
if (nanosleep(&ts, NULL) == -1)
err(1, "nanosleep");
if (write(fds[W], msg, sizeof(msg) - 1) == -1)
err(1, "write[2]");
close(fds[W]);
if ((errno = pthread_join(thrd, NULL)) != 0)
err(1, "pthread_join");
return EXIT_SUCCESS;
}
void *
work(void *_fds)
{
int *fds = _fds;
struct timespec ts = {.tv_nsec = 250 * MILLISECOND};
if (nanosleep(&ts, NULL) == -1)
err(1, "nanosleep");
pid_t pid = fork();
if (pid == -1)
err(1, "fork");
if (pid == 0) {
close(STDIN_FILENO);
if (dup2(fds[R], STDIN_FILENO) == -1)
err(1, "dup2");
close(fds[R]);
close(fds[W]);
execlp("cat", "cat", NULL);
err(1, "exec");
}
close(fds[R]);
if (wait(NULL) == -1)
err(1, "wait");
return NULL;
}
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