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LinuxThreads library.

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1998-03-11 00:42  Wolfram Gloger  <wmglo@dent.med.uni-muenchen.de>
	* linuxthreads/manager.c: Enable resetting of the thread
	scheduling policy to SCHED_OTHER when the parent thread
	has a different one.
1998-02-01 13:51  Ulrich Drepper  <drepper@cygnus.com>
	* sysdeps/unix/sysv/linux/bits/posix_opt.h: Define
	_POSIX_ASYNCHRONOUS_IO.
	* sysdeps/pthread/pthread.h: Define bits for Unix98 variants of
	mutexes.
	* mutex.c: Implement new mutex types.
	* internals.h: Include <signal.h>.
	* libpthread.map: Add __erno_location and __h_errno_location.
	* errno.c: Return pointer to variable actually in use.  This might
	not be the one in the thread structure.
	* internals.h (struct _pthread_descr_struct): Add new fields p_errnop
	and p_h_errnop.
	* manager.c (__pthread_manager): Set p_errnop and p_h_errnop member
	of manager thread structure.
	(pthread_handle_create): Set p_errnop and p_h_errnop members for new
	thread.
	* pthread.c: Adapt initializer for thread structures.
	(__pthread_initial_thread): Set p_errnop and p_h_errnop member.
	(__pthread_reset_main_thread): Reset p_errnop and p_h_errnop of
	current thread to global variables.
1998-01-31 17:27  Ulrich Drepper  <drepper@cygnus.com>
	* rwlock.c: New file.
	* Makefile (libpthread-routines): Add rwlock.
	* sysdeps/pthread/pthread.h: Define data structures and declare
	functions.
	* libpthread.map: Add new functions.
1997-12-18 13:50  Philip Blundell  <pb@nexus.co.uk>
	* sysdeps/arm/pt-machine.h: New file; add ARM support.
	* sysdeps/arm/Implies: likewise.
	* README: Document it.
1997-12-13  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>
	* signals.c: Remove unneeded initializer for sigwaited, saving a
1997-04-11 01:18  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>
	* semaphore.c (sem_init): Set sem_spinlock only if available.
1997-12-04 01:48  Ulrich Drepper  <drepper@cygnus.com>
	* mutex.c: Implement PTHREAD_MUTEX_CHECKERROR.
	* sysdeps/pthread/pthread.h: Define PTHREAD_MUTEX_CHECKERROR.
	* Makefile: Update from LinuxThreads 0.7.
	* internals.h. Likewise.
	* manager.c: Likewise.
	* mutex.c: Likewise.
	* pthread.c: Likewise.
	* signals.c: Likewise.
	* specific.c: Likewise.
	* Examples/ex3.c: Likewise.
1997-11-20 18:13  Ulrich Drepper  <drepper@cygnus.com>
	* pthread.c (__pthread_reset_main_thread): Close pipe only if still
	open.
1997-10-29 05:38  Ulrich Drepper  <drepper@cygnus.com>

	* wrapsyscall.c: Add socket functions which are also cancelation
	points.

1997-10-19 21:40  Wolfram Gloger  <wg@wolfram.dent.med.uni-muenchen.de>

	* specific.c (__libc_internal_tsd_set, __libc_internal_tsd_get):
	New functions for fast thread specific data within libc.

	* internals.h: Add new array p_libc_specific to struct
	_pthread_descr_struct.

	* sysdeps/pthread/bits/libc-lock.h: Declare new functions.

1997-10-13 05:39  Ulrich Drepper  <drepper@cygnus.com>

	* semaphore.h: Add __BEGIN_DECLS/__END_DECLS.
	Reported by Ralf Corsepius <corsepiu@faw.uni-ulm.de>.

1997-08-29 03:05  Ulrich Drepper  <drepper@cygnus.com>

	* internals.h (struct _pthread_descr_struct): Add definitions for
	two-level specific key handling.
	* manager.c (pthread_handle_create): Initialize specific memory array.
	* specific.c: Implement two-level key handling.
	* weaks.c: Don't provide dummy key handling.
	* sysdeps/pthread/bits/libc-lock.h: Typedef __libc_lock_t (no #define).
	Add definition of __libc_key_t.
	* sysdeps/unix/sysv/linux/bits/local_lim.h: Define PTHREAD_KEYS_MAX
	as 1024.
	Add definition of _POSIX_THREAD_DESTRUCTOR_ITERATIONS and
	PTHREAD_DESTRUCTOR_ITERATIONS.

	* manager.c (pthread_handle_create): Compare mmap result with
	MAP_FAILED.

	* ptfork.c: Rename to __pthread_atfork and make old name a weak alias.
	* sysdeps/pthread/bits/pthread.h: Add prototype for __pthread_atfork.

1997-08-22 19:04  Richard Henderson  <rth@cygnus.com>

	sysdeps/sparc -> sysdeps/sparc/sparc32
	sysdeps/sparc64 -> sysdeps/sparc/sparc64

	* internals.h: Change definition of THREAD_SELF to be an expression,
	not a statement that did a return.
	* sysdeps/alpha/pt-machine.h (THREAD_SELF): Update accordingly.
	* sysdeps/sparc/sparc32/pt-machine.h (THREAD_SELF, INIT_THREAD_SELF):
	Follow Solaris and use a "system reserved" register (%g6) to hold
	the thread descriptor.
	* sysdeps/sparc/sparc64/pt-machine.h: Likewise.

1997-08-03 00:09  Ulrich Drepper  <drepper@cygnus.com>

	* mutex.c: Correct pthread_once.  Patch by Xavier Leroy.
	* sysdeps/pthread/pthread.h: Add prototype for __pthread_once.
	* sysdeps/pthread/bits/pthread.h: Add macros for __libc_once.

	* semaphore.c: Include spinlock.h only when needed.

	* specific.c (__pthread_setsepcific, __pthread_getspecific): Reject
	keys for entries not in use.

	* weaks.c: Implement key handling functions for real.

1997-06-29  01:04  Richard Henderson  <richard@gnu.ai.mit.edu>

	Initial sparc64-linux support:
	* linuxthreads/sysdeps/sparc64/Implies: New file.
	* linuxthreads/sysdeps/sparc64/pt-machine.h: Likewise.

1997-06-29 00:48  Ulrich Drepper  <drepper@cygnus.com>

	* semaphore.c: Include spinlock.h at correct place.
	Patch by HJ Lu.

1997-06-13 10:06  Richard Henderson  <rth@tamu.edu>

	The Great Bit File Move:
	* sysdeps/alpha/semaphorebits.h: -> .../bits/semaphore.h.
	* sysdeps/powerpc/semaphorebits.h: Likewise.
	* sysdeps/pthread/cmpxchg/semaphorebits.h: Likewise.
	* sysdeps/pthread/no-cmpxchg/semaphorebits.h: Likewise.
	* sysdeps/pthread/libc-lock.h: -> bits/
	* sysdeps/pthread/stdio-lock.h: Likewise.
	* sysdeps/unix/sysv/linux/local_lim.h: Likewise.
	* sysdeps/unix/sysv/linux/posix_opt.h: Likewise.
	* semaphore.h: Likewise.
	* sysdeps/pthread/pthread.h: Likewise.

	* lockfile.c: <foo.h> -> <bits/foo.h>.
	* semaphore.h: Likewise.

	* Makefile: (headers): foo.h -> bits/foo.h.
	* sysdeps/pthread/Makefile: Likewise.

1997-04-11 01:18  Andreas Schwab  <schwab@issan.informatik.uni-dortmund.de>

	* semaphore.c (sem_init): Set sem_spinlock only if available.

	* sysdeps/m68k/pt-machine.h (testandset, __compare_and_swap): Fix
	asm constraints.

1997-04-09 03:00  Ulrich Drepper  <drepper@cygnus.com>

	Update from LinuxThreads 0.6.

	* attr.c (pthread_attr_getdetachstate): Use __sched_get_priority_max
	and __sched_get_priority_min instead of names without `__'.

	* manager.c: Rewrite large parts to implement opaque pthread_t.

	* cancel.c: Adapt for opaque pthread_t type.
	* condvar.c: Likewise.
	* errno.c: Likewise.
	* join.c: Likewise.
	* mutex.c: Likewise.
	* pthread.c: Likewise.
	* signals.c: Likewise.
	* specific.c: Likewise.
	* restart.h: Likewise.
	* queue.h: Likewise.
	* Examples/ex3.c: Likewise.
	* Examples/ex4.c: Likewise.
	* sysdeps/pthread/pthread.h: Likewise.

	* pthread.c: Accumulate time for all threads in thread manager.

	* semaphore.c: Implement fallback implementation for architectures
	sometimes missing compare-exchange operations.

	* cancel.c (pthread_cancel): Validate handle argument.
	* join.c (pthread_join): Likewise.
	(pthread_detach): Likewise.
	* signals.c (pthread_kill): Likewise.

	* spinlock.h (acquire): Use __sched_yield not sched_yield.

	* queue.h (enqueue): Enqueue thread according to priority.

	* internals.c (struct pthread_start_args): New struct for passing
	args to cloning function.
	(struct _pthread): Rename to _pthread_descr_struct and adapt for
	opaque pthread_t.

	* Examples/Makefile (clean): Pass -f option to rm.

	* sysdeps/i386/pt-machine.h: Add check for compare-exchange instruction
	and define TEST_FOR_COMPARE_AND_SWAP.
	* sysdeps/i386/i486/pt-machine.h: Removed.

	* sysdeps/unix/sysv/linux/local_lim.h (PTHREAD_THREADS_MAX): Increase
	to 1024.

1997-04-04 16:38  Ulrich Drepper  <drepper@cygnus.com>

	* restart.h (suspend): Clear p_signal before suspending.
	(suspend_with_cancellation): Likewise.
	Patch by Xavier Leroy <Xavier.Leroy@inria.fr>.

	* weaks.c: Make __pthread_key_create return 1.
	* sysdeps/pthread/libc-lock.h: Define __libc_key_create,
	__libc_getspecific, __libc_setspecific, and __libc_key_t.
	* sysdeps/pthread/stdio-lock.h: Don't care for implementation not
	using libio.

1997-03-19 15:13  Miguel de Icaza  <miguel@nuclecu.unam.mx>

	* sysdeps/sparc/pt-machine (RELEASE): Fix.

1997-03-01 07:55  Geoff Keating  <geoffk@ozemail.com.au>

	* sysdeps/powerpc/Implies: Added.
	* sysdeps/powerpc/pt-machine.h: Added.
	* sysdeps/powerpc/semaphorebits.h: Added.

1997-01-22 01:22  Ulrich Drepper  <drepper@cygnus.com>

	* linuxtheads/pthread.c (__pthread_initial_thread): Correct
	initializer.
	(__pthread_manager_thread): Likewise.
	Reported by Andreas Jaeger.

1997-01-18 22:15  Richard Henderson  <rth@tamu.edu>

	Since sigset_t no longer fits in a register, we can't pass in the
	thread's initial mask so easily.  Take this opportunity to simplify
	the clone implementation by only accepting a single void* argument.

	* linuxthreads/manager.c (__pthread_manager): Put thread vitals
	in the thread struct instead of as arguments through clone.
	(pthread_start_thread): Look for them there.
	* linuxthreads/internals.h (struct _pthread): Add p_initial_fn,
	p_initial_fn_arg, p_initial_mask.  Fix __pthread_manager proto.
	* linuxthreads/pthread.c (pthread_initialize_manager): Revise
	clone invocation.
This commit is contained in:
Ulrich Drepper
1998-03-11 12:42:25 +00:00
parent 3d76e77847
commit 5afdca0087
87 changed files with 10213 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
linuxthreads/Examples/Makefile Normal file
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CC=gcc
CFLAGS=-g -O -Wall -I.. -D_REENTRANT
LIBPTHREAD=../libpthread.a
PROGS=ex1 ex2 ex3 ex4 ex5 proxy
all: $(PROGS)
.c:
$(CC) $(CFLAGS) -o $* $*.c $(LIBPTHREAD)
$(PROGS):
clean:
rm -f $(PROGS)

36
linuxthreads/Examples/ex1.c Normal file
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/* Creates two threads, one printing 10000 "a"s, the other printing
10000 "b"s.
Illustrates: thread creation, thread joining. */
#include <stddef.h>
#include <stdio.h>
#include <unistd.h>
#include "pthread.h"
void * process(void * arg)
{
int i;
fprintf(stderr, "Starting process %s\n", (char *) arg);
for (i = 0; i < 10000; i++) {
write(1, (char *) arg, 1);
}
return NULL;
}
int main()
{
int retcode;
pthread_t th_a, th_b;
void * retval;
retcode = pthread_create(&th_a, NULL, process, "a");
if (retcode != 0) fprintf(stderr, "create a failed %d\n", retcode);
retcode = pthread_create(&th_b, NULL, process, "b");
if (retcode != 0) fprintf(stderr, "create b failed %d\n", retcode);
retcode = pthread_join(th_a, &retval);
if (retcode != 0) fprintf(stderr, "join a failed %d\n", retcode);
retcode = pthread_join(th_b, &retval);
if (retcode != 0) fprintf(stderr, "join b failed %d\n", retcode);
return 0;
}

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/* The classic producer-consumer example.
Illustrates mutexes and conditions.
All integers between 0 and 9999 should be printed exactly twice,
once to the right of the arrow and once to the left. */
#include <stdio.h>
#include "pthread.h"
#define BUFFER_SIZE 16
/* Circular buffer of integers. */
struct prodcons {
int buffer[BUFFER_SIZE]; /* the actual data */
pthread_mutex_t lock; /* mutex ensuring exclusive access to buffer */
int readpos, writepos; /* positions for reading and writing */
pthread_cond_t notempty; /* signaled when buffer is not empty */
pthread_cond_t notfull; /* signaled when buffer is not full */
};
/* Initialize a buffer */
void init(struct prodcons * b)
{
pthread_mutex_init(&b->lock, NULL);
pthread_cond_init(&b->notempty, NULL);
pthread_cond_init(&b->notfull, NULL);
b->readpos = 0;
b->writepos = 0;
}
/* Store an integer in the buffer */
void put(struct prodcons * b, int data)
{
pthread_mutex_lock(&b->lock);
/* Wait until buffer is not full */
while ((b->writepos + 1) % BUFFER_SIZE == b->readpos) {
pthread_cond_wait(&b->notfull, &b->lock);
/* pthread_cond_wait reacquired b->lock before returning */
}
/* Write the data and advance write pointer */
b->buffer[b->writepos] = data;
b->writepos++;
if (b->writepos >= BUFFER_SIZE) b->writepos = 0;
/* Signal that the buffer is now not empty */
pthread_cond_signal(&b->notempty);
pthread_mutex_unlock(&b->lock);
}
/* Read and remove an integer from the buffer */
int get(struct prodcons * b)
{
int data;
pthread_mutex_lock(&b->lock);
/* Wait until buffer is not empty */
while (b->writepos == b->readpos) {
pthread_cond_wait(&b->notempty, &b->lock);
}
/* Read the data and advance read pointer */
data = b->buffer[b->readpos];
b->readpos++;
if (b->readpos >= BUFFER_SIZE) b->readpos = 0;
/* Signal that the buffer is now not full */
pthread_cond_signal(&b->notfull);
pthread_mutex_unlock(&b->lock);
return data;
}
/* A test program: one thread inserts integers from 1 to 10000,
the other reads them and prints them. */
#define OVER (-1)
struct prodcons buffer;
void * producer(void * data)
{
int n;
for (n = 0; n < 10000; n++) {
printf("%d --->\n", n);
put(&buffer, n);
}
put(&buffer, OVER);
return NULL;
}
void * consumer(void * data)
{
int d;
while (1) {
d = get(&buffer);
if (d == OVER) break;
printf("---> %d\n", d);
}
return NULL;
}
int main()
{
pthread_t th_a, th_b;
void * retval;
init(&buffer);
/* Create the threads */
pthread_create(&th_a, NULL, producer, 0);
pthread_create(&th_b, NULL, consumer, 0);
/* Wait until producer and consumer finish. */
pthread_join(th_a, &retval);
pthread_join(th_b, &retval);
return 0;
}

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/* Multi-thread searching.
Illustrates: thread cancellation, cleanup handlers. */
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <pthread.h>
/* Defines the number of searching threads */
#define NUM_THREADS 5
/* Function prototypes */
void *search(void *);
void print_it(void *);
/* Global variables */
pthread_t threads[NUM_THREADS];
pthread_mutex_t lock;
int tries;
int main(argc, argv)
int argc;
char ** argv;
{
int i;
int pid;
/* create a number to search for */
pid = getpid();
printf("Searching for the number = %d...\n", pid);
/* Initialize the mutex lock */
pthread_mutex_init(&lock, NULL);
/* Create the searching threads */
for (i=0; i<NUM_THREADS; i++)
pthread_create(&threads[i], NULL, search, (void *)pid);
/* Wait for (join) all the searching threads */
for (i=0; i<NUM_THREADS; i++)
pthread_join(threads[i], NULL);
printf("It took %d tries to find the number.\n", tries);
/* Exit the program */
return 0;
}
/* This is the cleanup function that is called
when the threads are cancelled */
void print_it(void *arg)
{
int *try = (int *) arg;
pthread_t tid;
/* Get the calling thread's ID */
tid = pthread_self();
/* Print where the thread was in its search when it was cancelled */
printf("Thread %lx was canceled on its %d try.\n", tid, *try);
}
/* This is the search routine that is executed in each thread */
void *search(void *arg)
{
int num = (int) arg;
int i, j, ntries;
pthread_t tid;
/* get the calling thread ID */
tid = pthread_self();
/* use the thread ID to set the seed for the random number generator */
/* Since srand and rand are not thread-safe, serialize with lock */
pthread_mutex_lock(&lock);
srand((int)tid);
i = rand() & 0xFFFFFF;
pthread_mutex_unlock(&lock);
ntries = 0;
/* Set the cancellation parameters --
- Enable thread cancellation
- Defer the action of the cancellation */
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL);
/* Push the cleanup routine (print_it) onto the thread
cleanup stack. This routine will be called when the
thread is cancelled. Also note that the pthread_cleanup_push
call must have a matching pthread_cleanup_pop call. The
push and pop calls MUST be at the same lexical level
within the code */
/* Pass address of `ntries' since the current value of `ntries' is not
the one we want to use in the cleanup function */
pthread_cleanup_push(print_it, (void *)&ntries);
/* Loop forever */
while (1) {
i = (i + 1) & 0xFFFFFF;
ntries++;
/* Does the random number match the target number? */
if (num == i) {
/* Try to lock the mutex lock --
if locked, check to see if the thread has been cancelled
if not locked then continue */
while (pthread_mutex_trylock(&lock) == EBUSY)
pthread_testcancel();
/* Set the global variable for the number of tries */
tries = ntries;
printf("Thread %lx found the number!\n", tid);
/* Cancel all the other threads */
for (j=0; j<NUM_THREADS; j++)
if (threads[j] != tid) pthread_cancel(threads[j]);
/* Break out of the while loop */
break;
}
/* Every 100 tries check to see if the thread has been cancelled. */
if (ntries % 100 == 0) {
pthread_testcancel();
}
}
/* The only way we can get here is when the thread breaks out
of the while loop. In this case the thread that makes it here
has found the number we are looking for and does not need to run
the thread cleanup function. This is why the pthread_cleanup_pop
function is called with a 0 argument; this will pop the cleanup
function off the stack without executing it */
pthread_cleanup_pop(0);
return((void *)0);
}

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/* Making a library function that uses static variables thread-safe.
Illustrates: thread-specific data, pthread_once(). */
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
/* This is a typical example of a library function that uses
static variables to accumulate results between calls.
Here, it just returns the concatenation of all string arguments
that were given to it. */
#if 0
char * str_accumulate(char * s)
{
static char accu[1024] = { 0 };
strcat(accu, s);
return accu;
}
#endif
/* Of course, this cannot be used in a multi-threaded program
because all threads store "accu" at the same location.
So, we'll use thread-specific data to have a different "accu"
for each thread. */
/* Key identifying the thread-specific data */
static pthread_key_t str_key;
/* "Once" variable ensuring that the key for str_alloc will be allocated
exactly once. */
static pthread_once_t str_alloc_key_once = PTHREAD_ONCE_INIT;
/* Forward functions */
static void str_alloc_key(void);
static void str_alloc_destroy_accu(void * accu);
/* Thread-safe version of str_accumulate */
char * str_accumulate(char * s)
{
char * accu;
/* Make sure the key is allocated */
pthread_once(&str_alloc_key_once, str_alloc_key);
/* Get the thread-specific data associated with the key */
accu = (char *) pthread_getspecific(str_key);
/* It's initially NULL, meaning that we must allocate the buffer first. */
if (accu == NULL) {
accu = malloc(1024);
if (accu == NULL) return NULL;
accu[0] = 0;
/* Store the buffer pointer in the thread-specific data. */
pthread_setspecific(str_key, (void *) accu);
printf("Thread %lx: allocating buffer at %p\n", pthread_self(), accu);
}
/* Now we can use accu just as in the non thread-safe code. */
strcat(accu, s);
return accu;
}
/* Function to allocate the key for str_alloc thread-specific data. */
static void str_alloc_key(void)
{
pthread_key_create(&str_key, str_alloc_destroy_accu);
printf("Thread %lx: allocated key %d\n", pthread_self(), str_key);
}
/* Function to free the buffer when the thread exits. */
/* Called only when the thread-specific data is not NULL. */
static void str_alloc_destroy_accu(void * accu)
{
printf("Thread %lx: freeing buffer at %p\n", pthread_self(), accu);
free(accu);
}
/* Test program */
void * process(void * arg)
{
char * res;
res = str_accumulate("Result of ");
res = str_accumulate((char *) arg);
res = str_accumulate(" thread");
printf("Thread %lx: \"%s\"\n", pthread_self(), res);
return NULL;
}
int main(int argc, char ** argv)
{
char * res;
pthread_t th1, th2;
res = str_accumulate("Result of ");
pthread_create(&th1, NULL, process, "first");
pthread_create(&th2, NULL, process, "second");
res = str_accumulate("initial thread");
printf("Thread %lx: \"%s\"\n", pthread_self(), res);
pthread_join(th1, NULL);
pthread_join(th2, NULL);
pthread_exit(NULL);
}

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/* The classic producer-consumer example, implemented with semaphores.
All integers between 0 and 9999 should be printed exactly twice,
once to the right of the arrow and once to the left. */
#include <stdio.h>
#include "pthread.h"
#include "semaphore.h"
#define BUFFER_SIZE 16
/* Circular buffer of integers. */
struct prodcons {
int buffer[BUFFER_SIZE]; /* the actual data */
int readpos, writepos; /* positions for reading and writing */
sem_t sem_read; /* number of elements available for reading */
sem_t sem_write; /* number of locations available for writing */
};
/* Initialize a buffer */
void init(struct prodcons * b)
{
sem_init(&b->sem_write, 0, BUFFER_SIZE - 1);
sem_init(&b->sem_read, 0, 0);
b->readpos = 0;
b->writepos = 0;
}
/* Store an integer in the buffer */
void put(struct prodcons * b, int data)
{
/* Wait until buffer is not full */
sem_wait(&b->sem_write);
/* Write the data and advance write pointer */
b->buffer[b->writepos] = data;
b->writepos++;
if (b->writepos >= BUFFER_SIZE) b->writepos = 0;
/* Signal that the buffer contains one more element for reading */
sem_post(&b->sem_read);
}
/* Read and remove an integer from the buffer */
int get(struct prodcons * b)
{
int data;
/* Wait until buffer is not empty */
sem_wait(&b->sem_read);
/* Read the data and advance read pointer */
data = b->buffer[b->readpos];
b->readpos++;
if (b->readpos >= BUFFER_SIZE) b->readpos = 0;
/* Signal that the buffer has now one more location for writing */
sem_post(&b->sem_write);
return data;
}
/* A test program: one thread inserts integers from 1 to 10000,
the other reads them and prints them. */
#define OVER (-1)
struct prodcons buffer;
void * producer(void * data)
{
int n;
for (n = 0; n < 10000; n++) {
printf("%d --->\n", n);
put(&buffer, n);
}
put(&buffer, OVER);
return NULL;
}
void * consumer(void * data)
{
int d;
while (1) {
d = get(&buffer);
if (d == OVER) break;
printf("---> %d\n", d);
}
return NULL;
}
int main()
{
pthread_t th_a, th_b;
void * retval;
init(&buffer);
/* Create the threads */
pthread_create(&th_a, NULL, producer, 0);
pthread_create(&th_b, NULL, consumer, 0);
/* Wait until producer and consumer finish. */
pthread_join(th_a, &retval);
pthread_join(th_b, &retval);
return 0;
}