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glibc/linuxthreads/Examples/ex11.c
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/* Test program for timedout read/write lock functions. | |
Copyright (C) 2000 Free Software Foundation, Inc. | |
Contributed by Ulrich Drepper <drepper@redhat.com>, 2000. | |
The GNU C Library is free software; you can redistribute it and/or | |
modify it under the terms of the GNU Library General Public License as | |
published by the Free Software Foundation; either version 2 of the | |
License, or (at your option) any later version. | |
The GNU C Library 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 | |
Library General Public License for more details. | |
You should have received a copy of the GNU Library General Public | |
License along with the GNU C Library; see the file COPYING.LIB. If not, | |
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
Boston, MA 02111-1307, USA. */ | |
#include <errno.h> | |
#include <error.h> | |
#include <pthread.h> | |
#include <stdio.h> | |
#include <stdlib.h> | |
#include <time.h> | |
#include <unistd.h> | |
#define NWRITERS 15 | |
#define WRITETRIES 10 | |
#define NREADERS 15 | |
#define READTRIES 15 | |
#define TIMEOUT 1000000 | |
#define DELAY 1000000 | |
static pthread_rwlock_t lock = PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP; | |
static void * | |
writer_thread (void *nr) | |
{ | |
struct timespec ts; | |
struct timespec delay; | |
int n; | |
ts.tv_sec = 0; | |
ts.tv_nsec = TIMEOUT; | |
delay.tv_sec = 0; | |
delay.tv_nsec = DELAY; | |
for (n = 0; n < WRITETRIES; ++n) | |
{ | |
do | |
{ | |
clock_gettime (CLOCK_REALTIME, &ts); | |
ts.tv_nsec += 2 * TIMEOUT; | |
printf ("writer thread %ld tries again\n", (long int) nr); | |
} | |
//while (pthread_rwlock_wrlock (&lock), 0); | |
while (pthread_rwlock_timedwrlock (&lock, &ts) == ETIMEDOUT); | |
printf ("writer thread %ld succeeded\n", (long int) nr); | |
nanosleep (&delay, NULL); | |
pthread_rwlock_unlock (&lock); | |
printf ("writer thread %ld released\n", (long int) nr); | |
} | |
return NULL; | |
} | |
static void * | |
reader_thread (void *nr) | |
{ | |
struct timespec ts; | |
struct timespec delay; | |
int n; | |
delay.tv_sec = 0; | |
delay.tv_nsec = DELAY; | |
for (n = 0; n < READTRIES; ++n) | |
{ | |
do | |
{ | |
clock_gettime (CLOCK_REALTIME, &ts); | |
ts.tv_nsec += TIMEOUT; | |
printf ("reader thread %ld tries again\n", (long int) nr); | |
} | |
//while (pthread_rwlock_rdlock (&lock), 0); | |
while (pthread_rwlock_timedrdlock (&lock, &ts) == ETIMEDOUT); | |
printf ("reader thread %ld succeeded\n", (long int) nr); | |
nanosleep (&delay, NULL); | |
pthread_rwlock_unlock (&lock); | |
printf ("reader thread %ld released\n", (long int) nr); | |
} | |
return NULL; | |
} | |
int | |
main (void) | |
{ | |
pthread_t thwr[NWRITERS]; | |
pthread_t thrd[NREADERS]; | |
int n; | |
void *res; | |
/* Make standard error the same as standard output. */ | |
dup2 (1, 2); | |
/* Make sure we see all message, even those on stdout. */ | |
setvbuf (stdout, NULL, _IONBF, 0); | |
for (n = 0; n < NWRITERS; ++n) | |
{ | |
int err = pthread_create (&thwr[n], NULL, writer_thread, | |
(void *) (long int) n); | |
if (err != 0) | |
error (EXIT_FAILURE, err, "cannot create writer thread"); | |
} | |
for (n = 0; n < NREADERS; ++n) | |
{ | |
int err = pthread_create (&thrd[n], NULL, reader_thread, | |
(void *) (long int) n); | |
if (err != 0) | |
error (EXIT_FAILURE, err, "cannot create reader thread"); | |
} | |
/* Wait for all the threads. */ | |
for (n = 0; n < NWRITERS; ++n) | |
pthread_join (thwr[n], &res); | |
for (n = 0; n < NREADERS; ++n) | |
pthread_join (thrd[n], &res); | |
return 0; | |
} |