/* Copyright (C) 2002-2012 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _PTHREAD_H
#define _PTHREAD_H 1
#include <features.h>
#include <endian.h>
#include <sched.h>
#include <time.h>
#include <bits/pthreadtypes.h>
#include <bits/setjmp.h>
#include <bits/wordsize.h>
/* Detach state. */
enum
{
PTHREAD_CREATE_JOINABLE,
#define PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_JOINABLE
PTHREAD_CREATE_DETACHED
#define PTHREAD_CREATE_DETACHED PTHREAD_CREATE_DETACHED
};
/* Mutex types. */
enum
{
PTHREAD_MUTEX_TIMED_NP,
PTHREAD_MUTEX_RECURSIVE_NP,
PTHREAD_MUTEX_ERRORCHECK_NP,
PTHREAD_MUTEX_ADAPTIVE_NP
#if defined __USE_UNIX98 || defined __USE_XOPEN2K8
,
PTHREAD_MUTEX_NORMAL = PTHREAD_MUTEX_TIMED_NP,
PTHREAD_MUTEX_RECURSIVE = PTHREAD_MUTEX_RECURSIVE_NP,
PTHREAD_MUTEX_ERRORCHECK = PTHREAD_MUTEX_ERRORCHECK_NP,
PTHREAD_MUTEX_DEFAULT = PTHREAD_MUTEX_NORMAL
#endif
#ifdef __USE_GNU
/* For compatibility. */
, PTHREAD_MUTEX_FAST_NP = PTHREAD_MUTEX_TIMED_NP
#endif
};
#ifdef __USE_XOPEN2K
/* Robust mutex or not flags. */
enum
{
PTHREAD_MUTEX_STALLED,
PTHREAD_MUTEX_STALLED_NP = PTHREAD_MUTEX_STALLED,
PTHREAD_MUTEX_ROBUST,
PTHREAD_MUTEX_ROBUST_NP = PTHREAD_MUTEX_ROBUST
};
#endif
#if defined __USE_POSIX199506 || defined __USE_UNIX98
/* Mutex protocols. */
enum
{
PTHREAD_PRIO_NONE,
PTHREAD_PRIO_INHERIT,
PTHREAD_PRIO_PROTECT
};
#endif
#ifdef __PTHREAD_MUTEX_HAVE_PREV
# define PTHREAD_MUTEX_INITIALIZER \
{ { 0, 0, 0, 0, 0, __PTHREAD_SPINS, { 0, 0 } } }
# ifdef __USE_GNU
# define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, 0, PTHREAD_MUTEX_RECURSIVE_NP, __PTHREAD_SPINS, { 0, 0 } } }
# define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, 0, PTHREAD_MUTEX_ERRORCHECK_NP, __PTHREAD_SPINS, { 0, 0 } } }
# define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, 0, PTHREAD_MUTEX_ADAPTIVE_NP, __PTHREAD_SPINS, { 0, 0 } } }
# define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, 0, PTHREAD_MUTEX_ADAPTIVE_NP, __PTHREAD_SPINS, { 0, 0 } } }
# endif
#else
# define PTHREAD_MUTEX_INITIALIZER \
{ { 0, 0, 0, 0, 0, { __PTHREAD_SPINS } } }
# ifdef __USE_GNU
# define PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, PTHREAD_MUTEX_RECURSIVE_NP, 0, { __PTHREAD_SPINS } } }
# define PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, PTHREAD_MUTEX_ERRORCHECK_NP, 0, { __PTHREAD_SPINS } } }
# define PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP \
{ { 0, 0, 0, PTHREAD_MUTEX_ADAPTIVE_NP, 0, { __PTHREAD_SPINS } } }
# endif
#endif
/* Read-write lock types. */
#if defined __USE_UNIX98 || defined __USE_XOPEN2K
enum
{
PTHREAD_RWLOCK_PREFER_READER_NP,
PTHREAD_RWLOCK_PREFER_WRITER_NP,
PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,
PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP
};
/* Define __PTHREAD_RWLOCK_INT_FLAGS_SHARED to 1 if pthread_rwlock_t
has the shared field. All 64-bit architectures have the shared field
in pthread_rwlock_t. */
#ifndef __PTHREAD_RWLOCK_INT_FLAGS_SHARED
# if __WORDSIZE == 64
# define __PTHREAD_RWLOCK_INT_FLAGS_SHARED 1
# endif
#endif
/* Read-write lock initializers. */
# define PTHREAD_RWLOCK_INITIALIZER \
{ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }
# ifdef __USE_GNU
# ifdef __PTHREAD_RWLOCK_INT_FLAGS_SHARED
# define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
{ { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP } }
# else
# if __BYTE_ORDER == __LITTLE_ENDIAN
# define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
{ { 0, 0, 0, 0, 0, 0, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, \
0, 0, 0, 0 } }
# else
# define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
{ { 0, 0, 0, 0, 0, 0, 0, 0, 0, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,\
0 } }
# endif
# endif
# endif
#endif /* Unix98 or XOpen2K */
/* Scheduler inheritance. */
enum
{
PTHREAD_INHERIT_SCHED,
#define PTHREAD_INHERIT_SCHED PTHREAD_INHERIT_SCHED
PTHREAD_EXPLICIT_SCHED
#define PTHREAD_EXPLICIT_SCHED PTHREAD_EXPLICIT_SCHED
};
/* Scope handling. */
enum
{
PTHREAD_SCOPE_SYSTEM,
#define PTHREAD_SCOPE_SYSTEM PTHREAD_SCOPE_SYSTEM
PTHREAD_SCOPE_PROCESS
#define PTHREAD_SCOPE_PROCESS PTHREAD_SCOPE_PROCESS
};
/* Process shared or private flag. */
enum
{
PTHREAD_PROCESS_PRIVATE,
#define PTHREAD_PROCESS_PRIVATE PTHREAD_PROCESS_PRIVATE
PTHREAD_PROCESS_SHARED
#define PTHREAD_PROCESS_SHARED PTHREAD_PROCESS_SHARED
};
/* Conditional variable handling. */
#define PTHREAD_COND_INITIALIZER { { 0, 0, 0, 0, 0, (void *) 0, 0, 0 } }
/* Cleanup buffers */
struct _pthread_cleanup_buffer
{
void (*__routine) (void *); /* Function to call. */
void *__arg; /* Its argument. */
int __canceltype; /* Saved cancellation type. */
struct _pthread_cleanup_buffer *__prev; /* Chaining of cleanup functions. */
};
/* Cancellation */
enum
{
PTHREAD_CANCEL_ENABLE,
#define PTHREAD_CANCEL_ENABLE PTHREAD_CANCEL_ENABLE
PTHREAD_CANCEL_DISABLE
#define PTHREAD_CANCEL_DISABLE PTHREAD_CANCEL_DISABLE
};
enum
{
PTHREAD_CANCEL_DEFERRED,
#define PTHREAD_CANCEL_DEFERRED PTHREAD_CANCEL_DEFERRED
PTHREAD_CANCEL_ASYNCHRONOUS
#define PTHREAD_CANCEL_ASYNCHRONOUS PTHREAD_CANCEL_ASYNCHRONOUS
};
#define PTHREAD_CANCELED ((void *) -1)
/* Single execution handling. */
#define PTHREAD_ONCE_INIT 0
#ifdef __USE_XOPEN2K
/* Value returned by 'pthread_barrier_wait' for one of the threads after
the required number of threads have called this function.
-1 is distinct from 0 and all errno constants */
# define PTHREAD_BARRIER_SERIAL_THREAD -1
#endif
__BEGIN_DECLS
/* Create a new thread, starting with execution of START-ROUTINE
getting passed ARG. Creation attributed come from ATTR. The new
handle is stored in *NEWTHREAD. */
extern int pthread_create (pthread_t *__restrict __newthread,
const pthread_attr_t *__restrict __attr,
void *(*__start_routine) (void *),
void *__restrict __arg) __THROWNL __nonnull ((1, 3));
/* Terminate calling thread.
The registered cleanup handlers are called via exception handling
so we cannot mark this function with __THROW.*/
extern void pthread_exit (void *__retval) __attribute__ ((__noreturn__));
/* Make calling thread wait for termination of the thread TH. The
exit status of the thread is stored in *THREAD_RETURN, if THREAD_RETURN
is not NULL.
This function is a cancellation point and therefore not marked with
__THROW. */
extern int pthread_join (pthread_t __th, void **__thread_return);
#ifdef __USE_GNU
/* Check whether thread TH has terminated. If yes return the status of
the thread in *THREAD_RETURN, if THREAD_RETURN is not NULL. */
extern int pthread_tryjoin_np (pthread_t __th, void **__thread_return) __THROW;
/* Make calling thread wait for termination of the thread TH, but only
until TIMEOUT. The exit status of the thread is stored in
*THREAD_RETURN, if THREAD_RETURN is not NULL.
This function is a cancellation point and therefore not marked with
__THROW. */
extern int pthread_timedjoin_np (pthread_t __th, void **__thread_return,
const struct timespec *__abstime);
#endif
/* Indicate that the thread TH is never to be joined with PTHREAD_JOIN.
The resources of TH will therefore be freed immediately when it
terminates, instead of waiting for another thread to perform PTHREAD_JOIN
on it. */
extern int pthread_detach (pthread_t __th) __THROW;
/* Obtain the identifier of the current thread. */
extern pthread_t pthread_self (void) __THROW __attribute__ ((__const__));
/* Compare two thread identifiers. */
extern int pthread_equal (pthread_t __thread1, pthread_t __thread2)
__THROW __attribute__ ((__const__));
/* Thread attribute handling. */
/* Initialize thread attribute *ATTR with default attributes
(detachstate is PTHREAD_JOINABLE, scheduling policy is SCHED_OTHER,
no user-provided stack). */
extern int pthread_attr_init (pthread_attr_t *__attr) __THROW __nonnull ((1));
/* Destroy thread attribute *ATTR. */
extern int pthread_attr_destroy (pthread_attr_t *__attr)
__THROW __nonnull ((1));
/* Get detach state attribute. */
extern int pthread_attr_getdetachstate (const pthread_attr_t *__attr,
int *__detachstate)
__THROW __nonnull ((1, 2));
/* Set detach state attribute. */
extern int pthread_attr_setdetachstate (pthread_attr_t *__attr,
int __detachstate)
__THROW __nonnull ((1));
/* Get the size of the guard area created for stack overflow protection. */
extern int pthread_attr_getguardsize (const pthread_attr_t *__attr,
size_t *__guardsize)
__THROW __nonnull ((1, 2));
/* Set the size of the guard area created for stack overflow protection. */
extern int pthread_attr_setguardsize (pthread_attr_t *__attr,
size_t __guardsize)
__THROW __nonnull ((1));
/* Return in *PARAM the scheduling parameters of *ATTR. */
extern int pthread_attr_getschedparam (const pthread_attr_t *__restrict __attr,
struct sched_param *__restrict __param)
__THROW __nonnull ((1, 2));
/* Set scheduling parameters (priority, etc) in *ATTR according to PARAM. */
extern int pthread_attr_setschedparam (pthread_attr_t *__restrict __attr,
const struct sched_param *__restrict
__param) __THROW __nonnull ((1, 2));
/* Return in *POLICY the scheduling policy of *ATTR. */
extern int pthread_attr_getschedpolicy (const pthread_attr_t *__restrict
__attr, int *__restrict __policy)
__THROW __nonnull ((1, 2));
/* Set scheduling policy in *ATTR according to POLICY. */
extern int pthread_attr_setschedpolicy (pthread_attr_t *__attr, int __policy)
__THROW __nonnull ((1));
/* Return in *INHERIT the scheduling inheritance mode of *ATTR. */
extern int pthread_attr_getinheritsched (const pthread_attr_t *__restrict
__attr, int *__restrict __inherit)
__THROW __nonnull ((1, 2));
/* Set scheduling inheritance mode in *ATTR according to INHERIT. */
extern int pthread_attr_setinheritsched (pthread_attr_t *__attr,
int __inherit)
__THROW __nonnull ((1));
/* Return in *SCOPE the scheduling contention scope of *ATTR. */
extern int pthread_attr_getscope (const pthread_attr_t *__restrict __attr,
int *__restrict __scope)
__THROW __nonnull ((1, 2));
/* Set scheduling contention scope in *ATTR according to SCOPE. */
extern int pthread_attr_setscope (pthread_attr_t *__attr, int __scope)
__THROW __nonnull ((1));
/* Return the previously set address for the stack. */
extern int pthread_attr_getstackaddr (const pthread_attr_t *__restrict
__attr, void **__restrict __stackaddr)
__THROW __nonnull ((1, 2)) __attribute_deprecated__;
/* Set the starting address of the stack of the thread to be created.
Depending on whether the stack grows up or down the value must either
be higher or lower than all the address in the memory block. The
minimal size of the block must be PTHREAD_STACK_MIN. */
extern int pthread_attr_setstackaddr (pthread_attr_t *__attr,
void *__stackaddr)
__THROW __nonnull ((1)) __attribute_deprecated__;
/* Return the currently used minimal stack size. */
extern int pthread_attr_getstacksize (const pthread_attr_t *__restrict
__attr, size_t *__restrict __stacksize)
__THROW __nonnull ((1, 2));
/* Add information about the minimum stack size needed for the thread
to be started. This size must never be less than PTHREAD_STACK_MIN
and must also not exceed the system limits. */
extern int pthread_attr_setstacksize (pthread_attr_t *__attr,
size_t __stacksize)
__THROW __nonnull ((1));
#ifdef __USE_XOPEN2K
/* Return the previously set address for the stack. */
extern int pthread_attr_getstack (const pthread_attr_t *__restrict __attr,
void **__restrict __stackaddr,
size_t *__restrict __stacksize)
__THROW __nonnull ((1, 2, 3));
/* The following two interfaces are intended to replace the last two. They
require setting the address as well as the size since only setting the
address will make the implementation on some architectures impossible. */
extern int pthread_attr_setstack (pthread_attr_t *__attr, void *__stackaddr,
size_t __stacksize) __THROW __nonnull ((1));
#endif
#ifdef __USE_GNU
/* Thread created with attribute ATTR will be limited to run only on
the processors represented in CPUSET. */
extern int pthread_attr_setaffinity_np (pthread_attr_t *__attr,
size_t __cpusetsize,
const cpu_set_t *__cpuset)
__THROW __nonnull ((1, 3));
/* Get bit set in CPUSET representing the processors threads created with
ATTR can run on. */
extern int pthread_attr_getaffinity_np (const pthread_attr_t *__attr,
size_t __cpusetsize,
cpu_set_t *__cpuset)
__THROW __nonnull ((1, 3));
/* Initialize thread attribute *ATTR with attributes corresponding to the
already running thread TH. It shall be called on uninitialized ATTR
and destroyed with pthread_attr_destroy when no longer needed. */
extern int pthread_getattr_np (pthread_t __th, pthread_attr_t *__attr)
__THROW __nonnull ((2));
#endif
/* Functions for scheduling control. */
/* Set the scheduling parameters for TARGET_THREAD according to POLICY
and *PARAM. */
extern int pthread_setschedparam (pthread_t __target_thread, int __policy,
const struct sched_param *__param)
__THROW __nonnull ((3));
/* Return in *POLICY and *PARAM the scheduling parameters for TARGET_THREAD. */
extern int pthread_getschedparam (pthread_t __target_thread,
int *__restrict __policy,
struct sched_param *__restrict __param)
__THROW __nonnull ((2, 3));
/* Set the scheduling priority for TARGET_THREAD. */
extern int pthread_setschedprio (pthread_t __target_thread, int __prio)
__THROW;
#ifdef __USE_GNU
/* Get thread name visible in the kernel and its interfaces. */
extern int pthread_getname_np (pthread_t __target_thread, char *__buf,
size_t __buflen)
__THROW __nonnull ((2));
/* Set thread name visible in the kernel and its interfaces. */
extern int pthread_setname_np (pthread_t __target_thread, const char *__name)
__THROW __nonnull ((2));
#endif
#ifdef __USE_UNIX98
/* Determine level of concurrency. */
extern int pthread_getconcurrency (void) __THROW;
/* Set new concurrency level to LEVEL. */
extern int pthread_setconcurrency (int __level) __THROW;
#endif
#ifdef __USE_GNU
/* Yield the processor to another thread or process.
This function is similar to the POSIX `sched_yield' function but
might be differently implemented in the case of a m-on-n thread
implementation. */
extern int pthread_yield (void) __THROW;
/* Limit specified thread TH to run only on the processors represented
in CPUSET. */
extern int pthread_setaffinity_np (pthread_t __th, size_t __cpusetsize,
const cpu_set_t *__cpuset)
__THROW __nonnull ((3));
/* Get bit set in CPUSET representing the processors TH can run on. */
extern int pthread_getaffinity_np (pthread_t __th, size_t __cpusetsize,
cpu_set_t *__cpuset)
__THROW __nonnull ((3));
#endif
/* Functions for handling initialization. */
/* Guarantee that the initialization function INIT_ROUTINE will be called
only once, even if pthread_once is executed several times with the
same ONCE_CONTROL argument. ONCE_CONTROL must point to a static or
extern variable initialized to PTHREAD_ONCE_INIT.
The initialization functions might throw exception which is why
this function is not marked with __THROW. */
extern int pthread_once (pthread_once_t *__once_control,
void (*__init_routine) (void)) __nonnull ((1, 2));
/* Functions for handling cancellation.
Note that these functions are explicitly not marked to not throw an
exception in C++ code. If cancellation is implemented by unwinding
this is necessary to have the compiler generate the unwind information. */
/* Set cancelability state of current thread to STATE, returning old
state in *OLDSTATE if OLDSTATE is not NULL. */
extern int pthread_setcancelstate (int __state, int *__oldstate);
/* Set cancellation state of current thread to TYPE, returning the old
type in *OLDTYPE if OLDTYPE is not NULL. */
extern int pthread_setcanceltype (int __type, int *__oldtype);
/* Cancel THREAD immediately or at the next possibility. */
extern int pthread_cancel (pthread_t __th);
/* Test for pending cancellation for the current thread and terminate
the thread as per pthread_exit(PTHREAD_CANCELED) if it has been
cancelled. */
extern void pthread_testcancel (void);
/* Cancellation handling with integration into exception handling. */
typedef struct
{
struct
{
__jmp_buf __cancel_jmp_buf;
int __mask_was_saved;
} __cancel_jmp_buf[1];
void *__pad[4];
} __pthread_unwind_buf_t __attribute__ ((__aligned__));
/* No special attributes by default. */
#ifndef __cleanup_fct_attribute
# define __cleanup_fct_attribute
#endif
/* Structure to hold the cleanup handler information. */
struct __pthread_cleanup_frame
{
void (*__cancel_routine) (void *);
void *__cancel_arg;
int __do_it;
int __cancel_type;
};
#if defined __GNUC__ && defined __EXCEPTIONS
# ifdef __cplusplus
/* Class to handle cancellation handler invocation. */
class __pthread_cleanup_class
{
void (*__cancel_routine) (void *);
void *__cancel_arg;
int __do_it;
int __cancel_type;
public:
__pthread_cleanup_class (void (*__fct) (void *), void *__arg)
: __cancel_routine (__fct), __cancel_arg (__arg), __do_it (1) { }
~__pthread_cleanup_class () { if (__do_it) __cancel_routine (__cancel_arg); }
void __setdoit (int __newval) { __do_it = __newval; }
void __defer () { pthread_setcanceltype (PTHREAD_CANCEL_DEFERRED,
&__cancel_type); }
void __restore () const { pthread_setcanceltype (__cancel_type, 0); }
};
/* Install a cleanup handler: ROUTINE will be called with arguments ARG
when the thread is canceled or calls pthread_exit. ROUTINE will also
be called with arguments ARG when the matching pthread_cleanup_pop
is executed with non-zero EXECUTE argument.
pthread_cleanup_push and pthread_cleanup_pop are macros and must always
be used in matching pairs at the same nesting level of braces. */
# define pthread_cleanup_push(routine, arg) \
do { \
__pthread_cleanup_class __clframe (routine, arg)
/* Remove a cleanup handler installed by the matching pthread_cleanup_push.
If EXECUTE is non-zero, the handler function is called. */
# define pthread_cleanup_pop(execute) \
__clframe.__setdoit (execute); \
} while (0)
# ifdef __USE_GNU
/* Install a cleanup handler as pthread_cleanup_push does, but also
saves the current cancellation type and sets it to deferred
cancellation. */
# define pthread_cleanup_push_defer_np(routine, arg) \
do { \
__pthread_cleanup_class __clframe (routine, arg); \
__clframe.__defer ()
/* Remove a cleanup handler as pthread_cleanup_pop does, but also
restores the cancellation type that was in effect when the matching
pthread_cleanup_push_defer was called. */
# define pthread_cleanup_pop_restore_np(execute) \
__clframe.__restore (); \
__clframe.__setdoit (execute); \
} while (0)
# endif
# else
/* Function called to call the cleanup handler. As an extern inline
function the compiler is free to decide inlining the change when
needed or fall back on the copy which must exist somewhere
else. */
__extern_inline void
__pthread_cleanup_routine (struct __pthread_cleanup_frame *__frame)
{
if (__frame->__do_it)
__frame->__cancel_routine (__frame->__cancel_arg);
}
/* Install a cleanup handler: ROUTINE will be called with arguments ARG
when the thread is canceled or calls pthread_exit. ROUTINE will also
be called with arguments ARG when the matching pthread_cleanup_pop
is executed with non-zero EXECUTE argument.
pthread_cleanup_push and pthread_cleanup_pop are macros and must always
be used in matching pairs at the same nesting level of braces. */
# define pthread_cleanup_push(routine, arg) \
do { \
struct __pthread_cleanup_frame __clframe \
__attribute__ ((__cleanup__ (__pthread_cleanup_routine))) \
= { .__cancel_routine = (routine), .__cancel_arg = (arg), \
.__do_it = 1 };
/* Remove a cleanup handler installed by the matching pthread_cleanup_push.
If EXECUTE is non-zero, the handler function is called. */
# define pthread_cleanup_pop(execute) \
__clframe.__do_it = (execute); \
} while (0)
# ifdef __USE_GNU
/* Install a cleanup handler as pthread_cleanup_push does, but also
saves the current cancellation type and sets it to deferred
cancellation. */
# define pthread_cleanup_push_defer_np(routine, arg) \
do { \
struct __pthread_cleanup_frame __clframe \
__attribute__ ((__cleanup__ (__pthread_cleanup_routine))) \
= { .__cancel_routine = (routine), .__cancel_arg = (arg), \
.__do_it = 1 }; \
(void) pthread_setcanceltype (PTHREAD_CANCEL_DEFERRED, \
&__clframe.__cancel_type)
/* Remove a cleanup handler as pthread_cleanup_pop does, but also
restores the cancellation type that was in effect when the matching
pthread_cleanup_push_defer was called. */
# define pthread_cleanup_pop_restore_np(execute) \
(void) pthread_setcanceltype (__clframe.__cancel_type, NULL); \
__clframe.__do_it = (execute); \
} while (0)
# endif
# endif
#else
/* Install a cleanup handler: ROUTINE will be called with arguments ARG
when the thread is canceled or calls pthread_exit. ROUTINE will also
be called with arguments ARG when the matching pthread_cleanup_pop
is executed with non-zero EXECUTE argument.
pthread_cleanup_push and pthread_cleanup_pop are macros and must always
be used in matching pairs at the same nesting level of braces. */
# define pthread_cleanup_push(routine, arg) \
do { \
__pthread_unwind_buf_t __cancel_buf; \
void (*__cancel_routine) (void *) = (routine); \
void *__cancel_arg = (arg); \
int __not_first_call = __sigsetjmp ((struct __jmp_buf_tag *) (void *) \
__cancel_buf.__cancel_jmp_buf, 0); \
if (__glibc_unlikely (__not_first_call)) \
{ \
__cancel_routine (__cancel_arg); \
__pthread_unwind_next (&__cancel_buf); \
/* NOTREACHED */ \
} \
\
__pthread_register_cancel (&__cancel_buf); \
do {
extern void __pthread_register_cancel (__pthread_unwind_buf_t *__buf)
__cleanup_fct_attribute;
/* Remove a cleanup handler installed by the matching pthread_cleanup_push.
If EXECUTE is non-zero, the handler function is called. */
# define pthread_cleanup_pop(execute) \
do { } while (0);/* Empty to allow label before pthread_cleanup_pop. */\
} while (0); \
__pthread_unregister_cancel (&__cancel_buf); \
if (execute) \
__cancel_routine (__cancel_arg); \
} while (0)
extern void __pthread_unregister_cancel (__pthread_unwind_buf_t *__buf)
__cleanup_fct_attribute;
# ifdef __USE_GNU
/* Install a cleanup handler as pthread_cleanup_push does, but also
saves the current cancellation type and sets it to deferred
cancellation. */
# define pthread_cleanup_push_defer_np(routine, arg) \
do { \
__pthread_unwind_buf_t __cancel_buf; \
void (*__cancel_routine) (void *) = (routine); \
void *__cancel_arg = (arg); \
int __not_first_call = __sigsetjmp ((struct __jmp_buf_tag *) (void *) \
__cancel_buf.__cancel_jmp_buf, 0); \
if (__glibc_unlikely (__not_first_call)) \
{ \
__cancel_routine (__cancel_arg); \
__pthread_unwind_next (&__cancel_buf); \
/* NOTREACHED */ \
} \
\
__pthread_register_cancel_defer (&__cancel_buf); \
do {
extern void __pthread_register_cancel_defer (__pthread_unwind_buf_t *__buf)
__cleanup_fct_attribute;
/* Remove a cleanup handler as pthread_cleanup_pop does, but also
restores the cancellation type that was in effect when the matching
pthread_cleanup_push_defer was called. */
# define pthread_cleanup_pop_restore_np(execute) \
do { } while (0);/* Empty to allow label before pthread_cleanup_pop. */\
} while (0); \
__pthread_unregister_cancel_restore (&__cancel_buf); \
if (execute) \
__cancel_routine (__cancel_arg); \
} while (0)
extern void __pthread_unregister_cancel_restore (__pthread_unwind_buf_t *__buf)
__cleanup_fct_attribute;
# endif
/* Internal interface to initiate cleanup. */
extern void __pthread_unwind_next (__pthread_unwind_buf_t *__buf)
__cleanup_fct_attribute __attribute__ ((__noreturn__))
# ifndef SHARED
__attribute__ ((__weak__))
# endif
;
#endif
/* Function used in the macros. */
struct __jmp_buf_tag;
extern int __sigsetjmp (struct __jmp_buf_tag *__env, int __savemask) __THROWNL;
/* Mutex handling. */
/* Initialize a mutex. */
extern int pthread_mutex_init (pthread_mutex_t *__mutex,
const pthread_mutexattr_t *__mutexattr)
__THROW __nonnull ((1));
/* Destroy a mutex. */
extern int pthread_mutex_destroy (pthread_mutex_t *__mutex)
__THROW __nonnull ((1));
/* Try locking a mutex. */
extern int pthread_mutex_trylock (pthread_mutex_t *__mutex)
__THROWNL __nonnull ((1));
/* Lock a mutex. */
extern int pthread_mutex_lock (pthread_mutex_t *__mutex)
__THROWNL __nonnull ((1));
#ifdef __USE_XOPEN2K
/* Wait until lock becomes available, or specified time passes. */
extern int pthread_mutex_timedlock (pthread_mutex_t *__restrict __mutex,
const struct timespec *__restrict
__abstime) __THROWNL __nonnull ((1, 2));
#endif
/* Unlock a mutex. */
extern int pthread_mutex_unlock (pthread_mutex_t *__mutex)
__THROWNL __nonnull ((1));
/* Get the priority ceiling of MUTEX. */
extern int pthread_mutex_getprioceiling (const pthread_mutex_t *
__restrict __mutex,
int *__restrict __prioceiling)
__THROW __nonnull ((1, 2));
/* Set the priority ceiling of MUTEX to PRIOCEILING, return old
priority ceiling value in *OLD_CEILING. */
extern int pthread_mutex_setprioceiling (pthread_mutex_t *__restrict __mutex,
int __prioceiling,
int *__restrict __old_ceiling)
__THROW __nonnull ((1, 3));
#ifdef __USE_XOPEN2K8
/* Declare the state protected by MUTEX as consistent. */
extern int pthread_mutex_consistent (pthread_mutex_t *__mutex)
__THROW __nonnull ((1));
# ifdef __USE_GNU
extern int pthread_mutex_consistent_np (pthread_mutex_t *__mutex)
__THROW __nonnull ((1));
# endif
#endif
/* Functions for handling mutex attributes. */
/* Initialize mutex attribute object ATTR with default attributes
(kind is PTHREAD_MUTEX_TIMED_NP). */
extern int pthread_mutexattr_init (pthread_mutexattr_t *__attr)
__THROW __nonnull ((1));
/* Destroy mutex attribute object ATTR. */
extern int pthread_mutexattr_destroy (pthread_mutexattr_t *__attr)
__THROW __nonnull ((1));
/* Get the process-shared flag of the mutex attribute ATTR. */
extern int pthread_mutexattr_getpshared (const pthread_mutexattr_t *
__restrict __attr,
int *__restrict __pshared)
__THROW __nonnull ((1, 2));
/* Set the process-shared flag of the mutex attribute ATTR. */
extern int pthread_mutexattr_setpshared (pthread_mutexattr_t *__attr,
int __pshared)
__THROW __nonnull ((1));
#if defined __USE_UNIX98 || defined __USE_XOPEN2K8
/* Return in *KIND the mutex kind attribute in *ATTR. */
extern int pthread_mutexattr_gettype (const pthread_mutexattr_t *__restrict
__attr, int *__restrict __kind)
__THROW __nonnull ((1, 2));
/* Set the mutex kind attribute in *ATTR to KIND (either PTHREAD_MUTEX_NORMAL,
PTHREAD_MUTEX_RECURSIVE, PTHREAD_MUTEX_ERRORCHECK, or
PTHREAD_MUTEX_DEFAULT). */
extern int pthread_mutexattr_settype (pthread_mutexattr_t *__attr, int __kind)
__THROW __nonnull ((1));
#endif
/* Return in *PROTOCOL the mutex protocol attribute in *ATTR. */
extern int pthread_mutexattr_getprotocol (const pthread_mutexattr_t *
__restrict __attr,
int *__restrict __protocol)
__THROW __nonnull ((1, 2));
/* Set the mutex protocol attribute in *ATTR to PROTOCOL (either
PTHREAD_PRIO_NONE, PTHREAD_PRIO_INHERIT, or PTHREAD_PRIO_PROTECT). */
extern int pthread_mutexattr_setprotocol (pthread_mutexattr_t *__attr,
int __protocol)
__THROW __nonnull ((1));
/* Return in *PRIOCEILING the mutex prioceiling attribute in *ATTR. */
extern int pthread_mutexattr_getprioceiling (const pthread_mutexattr_t *
__restrict __attr,
int *__restrict __prioceiling)
__THROW __nonnull ((1, 2));
/* Set the mutex prioceiling attribute in *ATTR to PRIOCEILING. */
extern int pthread_mutexattr_setprioceiling (pthread_mutexattr_t *__attr,
int __prioceiling)
__THROW __nonnull ((1));
#ifdef __USE_XOPEN2K
/* Get the robustness flag of the mutex attribute ATTR. */
extern int pthread_mutexattr_getrobust (const pthread_mutexattr_t *__attr,
int *__robustness)
__THROW __nonnull ((1, 2));
# ifdef __USE_GNU
extern int pthread_mutexattr_getrobust_np (const pthread_mutexattr_t *__attr,
int *__robustness)
__THROW __nonnull ((1, 2));
# endif
/* Set the robustness flag of the mutex attribute ATTR. */
extern int pthread_mutexattr_setrobust (pthread_mutexattr_t *__attr,
int __robustness)
__THROW __nonnull ((1));
# ifdef __USE_GNU
extern int pthread_mutexattr_setrobust_np (pthread_mutexattr_t *__attr,
int __robustness)
__THROW __nonnull ((1));
# endif
#endif
#if defined __USE_UNIX98 || defined __USE_XOPEN2K
/* Functions for handling read-write locks. */
/* Initialize read-write lock RWLOCK using attributes ATTR, or use
the default values if later is NULL. */
extern int pthread_rwlock_init (pthread_rwlock_t *__restrict __rwlock,
const pthread_rwlockattr_t *__restrict
__attr) __THROW __nonnull ((1));
/* Destroy read-write lock RWLOCK. */
extern int pthread_rwlock_destroy (pthread_rwlock_t *__rwlock)
__THROW __nonnull ((1));
/* Acquire read lock for RWLOCK. */
extern int pthread_rwlock_rdlock (pthread_rwlock_t *__rwlock)
__THROWNL __nonnull ((1));
/* Try to acquire read lock for RWLOCK. */
extern int pthread_rwlock_tryrdlock (pthread_rwlock_t *__rwlock)
__THROWNL __nonnull ((1));
# ifdef __USE_XOPEN2K
/* Try to acquire read lock for RWLOCK or return after specfied time. */
extern int pthread_rwlock_timedrdlock (pthread_rwlock_t *__restrict __rwlock,
const struct timespec *__restrict
__abstime) __THROWNL __nonnull ((1, 2));
# endif
/* Acquire write lock for RWLOCK. */
extern int pthread_rwlock_wrlock (pthread_rwlock_t *__rwlock)
__THROWNL __nonnull ((1));
/* Try to acquire write lock for RWLOCK. */
extern int pthread_rwlock_trywrlock (pthread_rwlock_t *__rwlock)
__THROWNL __nonnull ((1));
# ifdef __USE_XOPEN2K
/* Try to acquire write lock for RWLOCK or return after specfied time. */
extern int pthread_rwlock_timedwrlock (pthread_rwlock_t *__restrict __rwlock,
const struct timespec *__restrict
__abstime) __THROWNL __nonnull ((1, 2));
# endif
/* Unlock RWLOCK. */
extern int pthread_rwlock_unlock (pthread_rwlock_t *__rwlock)
__THROWNL __nonnull ((1));
/* Functions for handling read-write lock attributes. */
/* Initialize attribute object ATTR with default values. */
extern int pthread_rwlockattr_init (pthread_rwlockattr_t *__attr)
__THROW __nonnull ((1));
/* Destroy attribute object ATTR. */
extern int pthread_rwlockattr_destroy (pthread_rwlockattr_t *__attr)
__THROW __nonnull ((1));
/* Return current setting of process-shared attribute of ATTR in PSHARED. */
extern int pthread_rwlockattr_getpshared (const pthread_rwlockattr_t *
__restrict __attr,
int *__restrict __pshared)
__THROW __nonnull ((1, 2));
/* Set process-shared attribute of ATTR to PSHARED. */
extern int pthread_rwlockattr_setpshared (pthread_rwlockattr_t *__attr,
int __pshared)
__THROW __nonnull ((1));
/* Return current setting of reader/writer preference. */
extern int pthread_rwlockattr_getkind_np (const pthread_rwlockattr_t *
__restrict __attr,
int *__restrict __pref)
__THROW __nonnull ((1, 2));
/* Set reader/write preference. */
extern int pthread_rwlockattr_setkind_np (pthread_rwlockattr_t *__attr,
int __pref) __THROW __nonnull ((1));
#endif
/* Functions for handling conditional variables. */
/* Initialize condition variable COND using attributes ATTR, or use
the default values if later is NULL. */
extern int pthread_cond_init (pthread_cond_t *__restrict __cond,
const pthread_condattr_t *__restrict __cond_attr)
__THROW __nonnull ((1));
/* Destroy condition variable COND. */
extern int pthread_cond_destroy (pthread_cond_t *__cond)
__THROW __nonnull ((1));
/* Wake up one thread waiting for condition variable COND. */
extern int pthread_cond_signal (pthread_cond_t *__cond)
__THROWNL __nonnull ((1));
/* Wake up all threads waiting for condition variables COND. */
extern int pthread_cond_broadcast (pthread_cond_t *__cond)
__THROWNL __nonnull ((1));
/* Wait for condition variable COND to be signaled or broadcast.
MUTEX is assumed to be locked before.
This function is a cancellation point and therefore not marked with
__THROW. */
extern int pthread_cond_wait (pthread_cond_t *__restrict __cond,
pthread_mutex_t *__restrict __mutex)
__nonnull ((1, 2));
/* Wait for condition variable COND to be signaled or broadcast until
ABSTIME. MUTEX is assumed to be locked before. ABSTIME is an
absolute time specification; zero is the beginning of the epoch
(00:00:00 GMT, January 1, 1970).
This function is a cancellation point and therefore not marked with
__THROW. */
extern int pthread_cond_timedwait (pthread_cond_t *__restrict __cond,
pthread_mutex_t *__restrict __mutex,
const struct timespec *__restrict __abstime)
__nonnull ((1, 2, 3));
/* Functions for handling condition variable attributes. */
/* Initialize condition variable attribute ATTR. */
extern int pthread_condattr_init (pthread_condattr_t *__attr)
__THROW __nonnull ((1));
/* Destroy condition variable attribute ATTR. */
extern int pthread_condattr_destroy (pthread_condattr_t *__attr)
__THROW __nonnull ((1));
/* Get the process-shared flag of the condition variable attribute ATTR. */
extern int pthread_condattr_getpshared (const pthread_condattr_t *
__restrict __attr,
int *__restrict __pshared)
__THROW __nonnull ((1, 2));
/* Set the process-shared flag of the condition variable attribute ATTR. */
extern int pthread_condattr_setpshared (pthread_condattr_t *__attr,
int __pshared) __THROW __nonnull ((1));
#ifdef __USE_XOPEN2K
/* Get the clock selected for the conditon variable attribute ATTR. */
extern int pthread_condattr_getclock (const pthread_condattr_t *
__restrict __attr,
__clockid_t *__restrict __clock_id)
__THROW __nonnull ((1, 2));
/* Set the clock selected for the conditon variable attribute ATTR. */
extern int pthread_condattr_setclock (pthread_condattr_t *__attr,
__clockid_t __clock_id)
__THROW __nonnull ((1));
#endif
#ifdef __USE_XOPEN2K
/* Functions to handle spinlocks. */
/* Initialize the spinlock LOCK. If PSHARED is nonzero the spinlock can
be shared between different processes. */
extern int pthread_spin_init (pthread_spinlock_t *__lock, int __pshared)
__THROW __nonnull ((1));
/* Destroy the spinlock LOCK. */
extern int pthread_spin_destroy (pthread_spinlock_t *__lock)
__THROW __nonnull ((1));
/* Wait until spinlock LOCK is retrieved. */
extern int pthread_spin_lock (pthread_spinlock_t *__lock)
__THROWNL __nonnull ((1));
/* Try to lock spinlock LOCK. */
extern int pthread_spin_trylock (pthread_spinlock_t *__lock)
__THROWNL __nonnull ((1));
/* Release spinlock LOCK. */
extern int pthread_spin_unlock (pthread_spinlock_t *__lock)
__THROWNL __nonnull ((1));
/* Functions to handle barriers. */
/* Initialize BARRIER with the attributes in ATTR. The barrier is
opened when COUNT waiters arrived. */
extern int pthread_barrier_init (pthread_barrier_t *__restrict __barrier,
const pthread_barrierattr_t *__restrict
__attr, unsigned int __count)
__THROW __nonnull ((1));
/* Destroy a previously dynamically initialized barrier BARRIER. */
extern int pthread_barrier_destroy (pthread_barrier_t *__barrier)
__THROW __nonnull ((1));
/* Wait on barrier BARRIER. */
extern int pthread_barrier_wait (pthread_barrier_t *__barrier)
__THROWNL __nonnull ((1));
/* Initialize barrier attribute ATTR. */
extern int pthread_barrierattr_init (pthread_barrierattr_t *__attr)
__THROW __nonnull ((1));
/* Destroy previously dynamically initialized barrier attribute ATTR. */
extern int pthread_barrierattr_destroy (pthread_barrierattr_t *__attr)
__THROW __nonnull ((1));
/* Get the process-shared flag of the barrier attribute ATTR. */
extern int pthread_barrierattr_getpshared (const pthread_barrierattr_t *
__restrict __attr,
int *__restrict __pshared)
__THROW __nonnull ((1, 2));
/* Set the process-shared flag of the barrier attribute ATTR. */
extern int pthread_barrierattr_setpshared (pthread_barrierattr_t *__attr,
int __pshared)
__THROW __nonnull ((1));
#endif
/* Functions for handling thread-specific data. */
/* Create a key value identifying a location in the thread-specific
data area. Each thread maintains a distinct thread-specific data
area. DESTR_FUNCTION, if non-NULL, is called with the value
associated to that key when the key is destroyed.
DESTR_FUNCTION is not called if the value associated is NULL when
the key is destroyed. */
extern int pthread_key_create (pthread_key_t *__key,
void (*__destr_function) (void *))
__THROW __nonnull ((1));
/* Destroy KEY. */
extern int pthread_key_delete (pthread_key_t __key) __THROW;
/* Return current value of the thread-specific data slot identified by KEY. */
extern void *pthread_getspecific (pthread_key_t __key) __THROW;
/* Store POINTER in the thread-specific data slot identified by KEY. */
extern int pthread_setspecific (pthread_key_t __key,
const void *__pointer) __THROW ;
#ifdef __USE_XOPEN2K
/* Get ID of CPU-time clock for thread THREAD_ID. */
extern int pthread_getcpuclockid (pthread_t __thread_id,
__clockid_t *__clock_id)
__THROW __nonnull ((2));
#endif
/* Install handlers to be called when a new process is created with FORK.
The PREPARE handler is called in the parent process just before performing
FORK. The PARENT handler is called in the parent process just after FORK.
The CHILD handler is called in the child process. Each of the three
handlers can be NULL, meaning that no handler needs to be called at that
point.
PTHREAD_ATFORK can be called several times, in which case the PREPARE
handlers are called in LIFO order (last added with PTHREAD_ATFORK,
first called before FORK), and the PARENT and CHILD handlers are called
in FIFO (first added, first called). */
extern int pthread_atfork (void (*__prepare) (void),
void (*__parent) (void),
void (*__child) (void)) __THROW;
#ifdef __USE_EXTERN_INLINES
/* Optimizations. */
__extern_inline int
__NTH (pthread_equal (pthread_t __thread1, pthread_t __thread2))
{
return __thread1 == __thread2;
}
#endif
__END_DECLS
#endif /* pthread.h */
Rosenblum TV: Video training, virtual workshops, classes, tutorials
RE-INVENTING THE TELEVISION NEWS BUSINESS*
A revolution in video storytelling
Creating entirely new & cost-effective production methods
From the world leaders in video production training and the creators of Character Driven Storytelling™
*and every other business that uses video
WHAT WE DO
Over the past 35 years, we have designed, built or restructured some of the most powerful news and journalism companies in the world.
We replace the traditional TV news ‘crew’ with one highly trained journalist, working alone with nothing but an iPhone.
No more TV news ‘crews’, no editors and no field producers.
This is television news done the way newspaper journalism is done – one reporter with their electronic pad and pencil.
In doing this, we can cut the cost of production by as much as 75% while increasing ratings and audience engagement.
In the place of conventional TV news ‘packages’ – ie, reporter stand up, interview, b-roll, man on the street, we marry great journalism with Netflix and Hollywood storytelling.
It’s a combination that works.
We have taken most of our clients to #1 in their respective markets.
And it’s not just for news. Any company, any profit, any NGO and anyone else who is online needs to tell their story in compelling yet cost-effective video. We can teach you to do that. Either in person or virtually.
EXAMPLES OF WHAT WE CAN TEACH YOUR STAFF TO PRODUCE
ITAY HOD
Itay Hod, MMJ with KPIX/CBS in San Francisco, took the 5-Day Intensive Video Storytelling Bootcamp in 2018.
Because he works alone, with only an iPhone, he was able to embed himself with a homeless family.
Here’s the story he produced in a one-day turn.
KIET DO
Kiet Do, an MMJ with KPIX/CBS in San Francisco, took the 5-Day Intensive Video Storytelling Bootcamp in 2021.
Here is a story he produced, all on his own, with only an iPhone and in a one-day turn.
TAYLOR SCHAUB
Taylor Schaub, an MMJ with Spectrum News 1 in LA, took the 5-Day Intensive Video Storytelling Bootcamp in 2023.
Here is a story he turned in only one day, using only an iPhone. It was the first video story he ever did and it was nominated for an Emmy.
THE BOOTCAMP
How do we convert stations and whole networks to working in this way?
Since 1988, we have run intensive 5-Day Video Storytelling Bootcamps
We have done these all over the world.
These are hands-on bootcamps, and participants learn an entirely new way of creating TV news stories.
-We shoot at a 3:1 ratio or lower, so turnaround times are fast.
-We go directly from camera to timelilne and edit – no written scripts. We work in the medium of pictures and sound.
-We are entirely character-driven.
-We are driven by pictures and real events.
-We are focused almost entirely on ’the viewer experience’.
Since 1988, more than 70,000 journalists around the world have taken our bootcamps, either in person on virtualy.
We have started to work with CBS News, bringing our ideas of character-driven storytelling to one of the most successful and biggest networks in the United States. Since beginning to work with them ratings have climbed and more importantly, audience engagement is through the ceiling.
We started New York Times Television in 1990 and it was the first paper to be brought into the world of TV. It quickly became one of the most successful non-fiction production companies in the United States. The series and documentaries we produced won many awards including multiple Emmys.
We have been working with the BBC since the year 2000 helping to convert their national news network to our visual storytelling technique. Most recently we have trained teams from their sports, documentaries, and comedy divisions to make character-driven stories using only smartphones.
For the past five years we have worked with Spectrum News to introduce and train their journalists on visual, character driven storytelling using smartphones helping to create a different kind of local news for their network of 24-Hour News Stations across the United States.
In 2006, we were approached by the United Nations. Rather than rely on news outlets, it would be much easier to train the field operatives to produce their own stories. We spent two years working with the UN, training more than 100 of their staff in bootcamps in Geneva and Nairobi.
We trained 50 print reporters at the paper to shoot and tell their own stories, in conjunction with their print work. We built a TV newsroom in their existing print newsroom – you could not ask for a better set and they began to live stream their stories in conjunction with their print work.
We spent two years with McGraw Hill, training more than 150 of their staffers, making them completely video literate. McGraw/Hill media properties we transit included Business Week, Aviation Week, (what was the name of the architecture magazine), and JD Power and Associates.
In 1990, we were approached by The Voice of America, the official broadcasting agency for the United States Government. When we met with VOA, they were only a short wave radio broadcaster, but working with them, we took them into television, launching VOA-TV.
British based Oyster Yachts makes some of the finest yachts in the world. Like every other company, they had to find a way to feed the never-ending video demands of social media – sites like Instagram and TikTok. We trained the Oyster staff to tell their own stories, using only iPhones.
We were approached by SEPA, the Scottish Environmental Protection Agency because they had to continually find a way to ‘feed the media beast’. The result was that SEPA was able to tell their own stories, whenever they wanted, and at almost no additional cost.
Michael Rosenblum has been writing about the media since 1988. His work and ideas have appeared in The Guardian, The Huffington Post, Ilkeston Life and many other publications.
He has been blogging regularly for the past 35 years on this subject. Having taught media studies at Columbia University, NYU and now the University of Oxford, he is considered an expert on this subject.
Continue reading this post or look back at previous posts.
