2018-12-01 10:45:51 -08:00

46 lines
948 B
C

#include <stdio.h>
#include <pthread.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static pthread_t tid[2];
static void *startproc(void *arg)
{
pid_t pid;
char *argv[] = { "/bin/ls", "/bin/ls", NULL };
if ((pid = fork()) == -1) {
perror("fork error");
} else if (pid == 0) {
dup2(2, 1); // redirect stdout to stderr
execv(argv[0], argv); // child
}
return NULL;
}
int main(int argc, char **argv)
{
// No arguments means serialize the fork() calls. One argument means perform
// both fork() calls concurrently.
int serialize_fork = argc == 1;
int i = 0;
int err;
for (i = 0; i < 2; i++) {
err = pthread_create(&tid[i], NULL, &startproc, NULL);
if (err != 0)
perror("pthread_create()");
if (serialize_fork)
pthread_join(tid[i], NULL);
}
if (!serialize_fork) {
for (i = 0; i < 2; i++)
if (tid[i])
pthread_join(tid[i], NULL);
}
return 0;
}