1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
|
/* This testcase is part of GDB, the GNU debugger.
Copyright 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <assert.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#define NUMTHREADS 10
volatile int done = 0;
static pthread_barrier_t barrier;
static void *
start (void *arg)
{
while (!done)
usleep (100);
assert (0);
return arg;
}
void *
thread_function (void *arg)
{
int x = * (int *) arg;
printf ("Thread <%d> executing\n", x);
pthread_barrier_wait (&barrier);
while (!done)
usleep (100);
return NULL;
}
void *
thread_forker (void *arg)
{
int x = * (int *) arg;
pid_t pid;
int rv;
int i;
pthread_t thread;
printf ("Thread forker <%d> executing\n", x);
pthread_barrier_wait (&barrier);
switch ((pid = fork ()))
{
case -1:
assert (0);
default:
wait (&rv);
done = 1;
break;
case 0:
i = pthread_create (&thread, NULL, start, NULL);
assert (i == 0);
i = pthread_join (thread, NULL);
assert (i == 0);
assert (0);
}
return NULL;
}
int
main (void)
{
pthread_t threads[NUMTHREADS];
int args[NUMTHREADS];
int i, j;
i = pthread_barrier_init (&barrier, NULL, NUMTHREADS);
assert (i == 0);
/* Create a few threads that do mostly nothing, and then one that
forks. */
for (j = 0; j < NUMTHREADS - 1; ++j)
{
args[j] = j;
pthread_create (&threads[j], NULL, thread_function, &args[j]);
}
args[j] = j;
pthread_create (&threads[j], NULL, thread_forker, &args[j]);
for (j = 0; j < NUMTHREADS; ++j)
{
pthread_join (threads[j], NULL);
}
return 0;
}
|
