18. Thread Manager#
18.1. Introduction#
The thread manager implements the functionality required of the thread manager as defined by POSIX 1003.1b. This standard requires that a compliant operating system provide the facilties to manage multiple threads of control and defines the API that must be provided.
The services provided by the thread manager are:
pthread_attr_init - Initialize a Thread Attribute Set
pthread_attr_destroy - Destroy a Thread Attribute Set
pthread_attr_setdetachstate - Set Detach State
pthread_attr_getdetachstate - Get Detach State
pthread_attr_setstacksize - Set Thread Stack Size
pthread_attr_getstacksize - Get Thread Stack Size
pthread_attr_setstackaddr - Set Thread Stack Address
pthread_attr_getstackaddr - Get Thread Stack Address
pthread_attr_setscope - Set Thread Scheduling Scope
pthread_attr_getscope - Get Thread Scheduling Scope
pthread_attr_setinheritsched - Set Inherit Scheduler Flag
pthread_attr_getinheritsched - Get Inherit Scheduler Flag
pthread_attr_setschedpolicy - Set Scheduling Policy
pthread_attr_getschedpolicy - Get Scheduling Policy
pthread_attr_setschedparam - Set Scheduling Parameters
pthread_attr_getschedparam - Get Scheduling Parameters
pthread_attr_getaffinity_np - Get Thread Affinity Attribute
pthread_attr_setaffinity_np - Set Thread Affinity Attribute
pthread_create - Create a Thread
pthread_exit - Terminate the Current Thread
pthread_detach - Detach a Thread
pthread_getconcurrency - Get Thread Level of Concurrency
pthread_setconcurrency - Set Thread Level of Concurrency
pthread_getattr_np - Get Thread Attributes
pthread_join - Wait for Thread Termination
pthread_self - Get Thread ID
pthread_equal - Compare Thread IDs
pthread_once - Dynamic Package Initialization
pthread_setschedparam - Set Thread Scheduling Parameters
pthread_getschedparam - Get Thread Scheduling Parameters
pthread_getaffinity_np - Get Thread Affinity
pthread_setaffinity_np - Set Thread Affinity
18.2. Background#
18.2.1. Thread Attributes#
Thread attributes are utilized only at thread creation time. A thread attribute
structure may be initialized and passed as an argument to the
pthread_create
routine.
- stack address
is the address of the optionally user specified stack area for this thread. If this value is NULL, then RTEMS allocates the memory for the thread stack from the RTEMS Workspace Area. Otherwise, this is the user specified address for the memory to be used for the thread’s stack. Each thread must have a distinct stack area. Each processor family has different alignment rules which should be followed.
- stack size
is the minimum desired size for this thread’s stack area. If the size of this area as specified by the stack size attribute is smaller than the minimum for this processor family and the stack is not user specified, then RTEMS will automatically allocate a stack of the minimum size for this processor family.
- contention scope
specifies the scheduling contention scope. RTEMS only supports the PTHREAD_SCOPE_PROCESS scheduling contention scope.
- scheduling inheritance
specifies whether a user specified or the scheduling policy and parameters of the currently executing thread are to be used. When this is PTHREAD_INHERIT_SCHED, then the scheduling policy and parameters of the currently executing thread are inherited by the newly created thread.
- scheduling policy and parameters
specify the manner in which the thread will contend for the processor. The scheduling parameters are interpreted based on the specified policy. All policies utilize the thread priority parameter.
18.3. Operations#
There is currently no text in this section.
18.4. Services#
This section details the thread manager’s services. A subsection is dedicated to each of this manager’s services and describes the calling sequence, related constants, usage, and status codes.
18.4.1. pthread_attr_init - Initialize a Thread Attribute Set#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_init(
pthread_attr_t *attr
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
DESCRIPTION:
The pthread_attr_init
routine initializes the thread attributes object
specified by attr
with the default value for all of the individual
attributes.
NOTES:
The settings in the default attributes are implementation defined. For RTEMS, the default attributes are as follows:
stackadr |
is not set to indicate that RTEMS is to allocate the stack memory. |
stacksize |
is set to |
contentionscope |
is set to |
inheritsched |
is set to |
detachstate |
is set to |
18.4.2. pthread_attr_destroy - Destroy a Thread Attribute Set#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_destroy(
pthread_attr_t *attr
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
DESCRIPTION:
The pthread_attr_destroy
routine is used to destroy a thread attributes
object. The behavior of using an attributes object after it is destroyed is
implementation dependent.
NOTES:
NONE
18.4.3. pthread_attr_setdetachstate - Set Detach State#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setdetachstate(
pthread_attr_t *attr,
int detachstate
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The detachstate argument is invalid. |
DESCRIPTION:
The pthread_attr_setdetachstate
routine is used to value of the
detachstate
attribute. This attribute controls whether the thread is
created in a detached state.
The detachstate
can be either PTHREAD_CREATE_DETACHED
or
PTHREAD_CREATE_JOINABLE
. The default value for all threads is
PTHREAD_CREATE_JOINABLE
.
NOTES:
If a thread is in a detached state, then the use of the ID with the
pthread_detach
or pthread_join
routines is an error.
18.4.4. pthread_attr_getdetachstate - Get Detach State#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getdetachstate(
const pthread_attr_t *attr,
int *detachstate
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The detatchstate pointer argument is invalid. |
DESCRIPTION:
The pthread_attr_getdetachstate
routine is used to obtain the current value
of the detachstate
attribute as specified by the attr
thread attribute
object.
NOTES:
NONE
18.4.5. pthread_attr_setstacksize - Set Thread Stack Size#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setstacksize(
pthread_attr_t *attr,
size_t stacksize
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
DESCRIPTION:
The pthread_attr_setstacksize
routine is used to set the stacksize
attribute in the attr
thread attribute object.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_ATTR_STACKSIZE
to indicate that this routine is supported.
If the specified stacksize is below the minimum required for this CPU
(PTHREAD_STACK_MIN
, then the stacksize will be set to the minimum for this
CPU.
18.4.6. pthread_attr_getstacksize - Get Thread Stack Size#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getstacksize(
const pthread_attr_t *attr,
size_t *stacksize
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The stacksize pointer argument is invalid. |
DESCRIPTION:
The pthread_attr_getstacksize
routine is used to obtain the stacksize
attribute in the attr
thread attribute object.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_ATTR_STACKSIZE
to indicate that this routine is supported.
18.4.7. pthread_attr_setstackaddr - Set Thread Stack Address#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setstackaddr(
pthread_attr_t *attr,
void *stackaddr
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
DESCRIPTION:
The pthread_attr_setstackaddr
routine is used to set the stackaddr
attribute in the attr
thread attribute object.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_ATTR_STACKADDR
to indicate that this routine is supported.
It is imperative to the proper operation of the system that each thread have sufficient stack space.
18.4.8. pthread_attr_getstackaddr - Get Thread Stack Address#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getstackaddr(
const pthread_attr_t *attr,
void **stackaddr
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The stackaddr pointer argument is invalid. |
DESCRIPTION:
The pthread_attr_getstackaddr
routine is used to obtain the stackaddr
attribute in the attr
thread attribute object.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_ATTR_STACKADDR
to indicate that this routine is supported.
18.4.9. pthread_attr_setscope - Set Thread Scheduling Scope#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setscope(
pthread_attr_t *attr,
int contentionscope
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The contention scope specified is not valid. |
|
The contention scope specified ( |
DESCRIPTION:
The pthread_attr_setscope
routine is used to set the contention scope field
in the thread attribute object attr
to the value specified by
contentionscope
.
The contentionscope
must be either PTHREAD_SCOPE_SYSTEM
to indicate
that the thread is to be within system scheduling contention or
PTHREAD_SCOPE_PROCESS
indicating that the thread is to be within the
process scheduling contention scope.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.10. pthread_attr_getscope - Get Thread Scheduling Scope#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getscope(
const pthread_attr_t *attr,
int *contentionscope
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The contentionscope pointer argument is invalid. |
DESCRIPTION:
The pthread_attr_getscope
routine is used to obtain the value of the
contention scope field in the thread attributes object attr
. The current
value is returned in contentionscope
.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.11. pthread_attr_setinheritsched - Set Inherit Scheduler Flag#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setinheritsched(
pthread_attr_t *attr,
int inheritsched
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The specified scheduler inheritance argument is invalid. |
DESCRIPTION:
The pthread_attr_setinheritsched
routine is used to set the inherit
scheduler field in the thread attribute object attr
to the value specified
by inheritsched
.
The contentionscope
must be either PTHREAD_INHERIT_SCHED
to indicate
that the thread is to inherit the scheduling policy and parameters fromthe
creating thread, or PTHREAD_EXPLICIT_SCHED
to indicate that the scheduling
policy and parameters for this thread are to be set from the corresponding
values in the attributes object. If contentionscope
is
PTHREAD_INHERIT_SCHED
, then the scheduling attributes in the attr
structure will be ignored at thread creation time.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.12. pthread_attr_getinheritsched - Get Inherit Scheduler Flag#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getinheritsched(
const pthread_attr_t *attr,
int *inheritsched
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The inheritsched pointer argument is invalid. |
DESCRIPTION:
The pthread_attr_getinheritsched
routine is used to object the current
value of the inherit scheduler field in the thread attribute object attr
.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.13. pthread_attr_setschedpolicy - Set Scheduling Policy#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setschedpolicy(
pthread_attr_t *attr,
int policy
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The specified scheduler policy argument is invalid. |
DESCRIPTION:
The pthread_attr_setschedpolicy
routine is used to set the scheduler policy
field in the thread attribute object attr
to the value specified by
policy
.
Scheduling policies may be one of the following:
SCHED_DEFAULT
SCHED_FIFO
SCHED_RR
SCHED_SPORADIC
SCHED_OTHER
The precise meaning of each of these is discussed elsewhere in this manual.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.14. pthread_attr_getschedpolicy - Get Scheduling Policy#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getschedpolicy(
const pthread_attr_t *attr,
int *policy
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The specified scheduler policy argument pointer is invalid. |
DESCRIPTION:
The pthread_attr_getschedpolicy
routine is used to obtain the scheduler
policy field from the thread attribute object attr
. The value of this
field is returned in policy
.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.15. pthread_attr_setschedparam - Set Scheduling Parameters#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_setschedparam(
pthread_attr_t *attr,
const struct sched_param param
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The specified scheduler parameter argument is invalid. |
DESCRIPTION:
The pthread_attr_setschedparam
routine is used to set the scheduler
parameters field in the thread attribute object attr
to the value specified
by param
.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.16. pthread_attr_getschedparam - Get Scheduling Parameters#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_attr_getschedparam(
const pthread_attr_t *attr,
struct sched_param *param
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The attribute set is not initialized. |
|
The specified scheduler parameter argument pointer is invalid. |
DESCRIPTION:
The pthread_attr_getschedparam
routine is used to obtain the scheduler
parameters field from the thread attribute object attr
. The value of this
field is returned in param
.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.17. pthread_attr_getaffinity_np - Get Thread Affinity Attribute#
CALLING SEQUENCE:
#define _GNU_SOURCE
#include <pthread.h>
int pthread_attr_getaffinity_np(
const pthread_attr_t *attr,
size_t cpusetsize,
cpu_set_t *cpuset
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The cpuset pointer argument is invalid. |
|
The |
DESCRIPTION:
The pthread_attr_getaffinity_np
routine is used to obtain the
affinityset
field from the thread attribute object attr
. The value of
this field is returned in cpuset
.
NOTES:
NONE
18.4.18. pthread_attr_setaffinity_np - Set Thread Affinity Attribute#
CALLING SEQUENCE:
#define _GNU_SOURCE
#include <pthread.h>
int pthread_attr_setaffinity_np(
pthread_attr_t *attr,
size_t cpusetsize,
const cpu_set_t *cpuset
);
STATUS CODES:
|
The attribute pointer argument is invalid. |
|
The cpuset pointer argument is invalid. |
|
The |
|
The |
|
The |
DESCRIPTION:
The pthread_attr_setaffinity_np
routine is used to set the affinityset
field in the thread attribute object attr
. The value of this field is
returned in cpuset
.
NOTES:
NONE
18.4.19. pthread_create - Create a Thread#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_create(
pthread_t *thread,
const pthread_attr_t *attr,
void (*start_routine)( void *),
void *arg
);
STATUS CODES:
|
The attribute set is not initialized. |
|
The user specified a stack address and the size of the area was not large enough to meet this processor’s minimum stack requirements. |
|
The specified scheduler inheritance policy was invalid. |
|
The specified contention scope was |
|
The specified thread priority was invalid. |
|
The specified scheduling policy was invalid. |
|
The scheduling policy was |
|
The scheduling policy was |
|
The system lacked the necessary resources to create another thread, or the
self imposed limit on the total number of threads in a process
|
|
Invalid argument passed. |
DESCRIPTION:
The pthread_create
routine is used to create a new thread with the
attributes specified by attr
. If the attr
argument is NULL
, then
the default attribute set will be used. Modification of the contents of
attr
after this thread is created does not have an impact on this thread.
The thread begins execution at the address specified by start_routine
with
arg
as its only argument. If start_routine
returns, then it is
functionally equivalent to the thread executing the pthread_exit
service.
Upon successful completion, the ID of the created thread is returned in the
thread
argument.
NOTES:
There is no concept of a single main thread in RTEMS as there is in a tradition
UNIX system. POSIX requires that the implicit return of the main thread results
in the same effects as if there were a call to exit
. This does not occur in
RTEMS.
The signal mask of the newly created thread is inherited from its creator and the set of pending signals for this thread is empty.
18.4.20. pthread_exit - Terminate the Current Thread#
CALLING SEQUENCE:
#include <pthread.h>
void pthread_exit(
void *status
);
STATUS CODES:
NONE
DESCRIPTION:
The pthread_exit
routine is used to terminate the calling thread. The
status
is made available to any successful join with the terminating
thread.
When a thread returns from its start routine, it results in an implicit call to
the pthread_exit
routine with the return value of the function serving as
the argument to pthread_exit
.
NOTES:
Any cancellation cleanup handlers that hace been pushed and not yet popped shall be popped in reverse of the order that they were pushed. After all cancellation cleanup handlers have been executed, if the thread has any thread-specific data, destructors for that data will be invoked.
Thread termination does not release or free any application visible resources including byt not limited to mutexes, file descriptors, allocated memory, etc.. Similarly, exitting a thread does not result in any process-oriented cleanup activity.
There is no concept of a single main thread in RTEMS as there is in a tradition
UNIX system. POSIX requires that the implicit return of the main thread results
in the same effects as if there were a call to exit
. This does not occur in
RTEMS.
All access to any automatic variables allocated by the threads is lost when the thread exits. Thus references (i.e. pointers) to local variables of a thread should not be used in a global manner without care. As a specific example, a pointer to a local variable should NOT be used as the return value.
18.4.21. pthread_detach - Detach a Thread#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_detach(
pthread_t thread
);
STATUS CODES:
|
The thread specified is invalid. |
|
The thread specified is not a joinable thread. |
DESCRIPTION:
The pthread_detach
routine is used to to indicate that storage for
thread
can be reclaimed when the thread terminates without another thread
joinging with it.
NOTES:
If any threads have previously joined with the specified thread, then they will
remain joined with that thread. Any subsequent calls to pthread_join
on the
specified thread will fail.
18.4.22. pthread_getconcurrency - Obtain Thread Concurrency#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_getconcurrency(void);
STATUS CODES:
This method returns the current concurrency mapping value.
DESCRIPTION:
The pthread_getconcurrency
method returns the number of user threads
mapped onto kernel threads. For RTEMS, user and kernel threads are mapped
1:1 and per the POSIX standard this method returns 1 initially and
the value last set by pthread_setconcurrency
otherwise.
NOTES:
NONE
18.4.23. pthread_setconcurrency - Set Thread Concurrency#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_setconcurrency(void);
STATUS CODES:
This method returns 0 on success.
DESCRIPTION:
The pthread_setconcurrency
method requests the number of user threads
mapped onto kernel threads. Per the POSIX standard, this is considered
a request and may have no impact.
For RTEMS, user and kernel threads are always mapped 1:1 and thus this
method has no change on the mapping. However, pthread_getconcurrency
will return the value set.
NOTES:
NONE
18.4.24. pthread_getattr_np - Get Thread Attributes#
CALLING SEQUENCE:
#define _GNU_SOURCE
#include <pthread.h>
int pthread_getattr_np(
pthread_t thread,
pthread_attr_t *attr
);
STATUS CODES:
|
The thread specified is invalid. |
|
The attribute pointer argument is invalid. |
DESCRIPTION:
The pthread_getattr_np
routine is used to obtain the attributes associated
with thread
.
NOTES:
Modification of the execution modes and priority through the Classic API may result in a combination that is not representable in the POSIX API.
18.4.25. pthread_join - Wait for Thread Termination#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_join(
pthread_t thread,
void **value_ptr
);
STATUS CODES:
|
The thread specified is invalid. |
|
The thread specified is not a joinable thread. |
|
A deadlock was detected or thread is the calling thread. |
DESCRIPTION:
The pthread_join
routine suspends execution of the calling thread until
thread
terminates. If thread
has already terminated, then this routine
returns immediately. The value returned by thread
(i.e. passed to
pthread_exit
is returned in value_ptr
.
When this routine returns, then thread
has been terminated.
NOTES:
The results of multiple simultaneous joins on the same thread is undefined.
If any threads have previously joined with the specified thread, then they will
remain joined with that thread. Any subsequent calls to pthread_join
on the
specified thread will fail.
If value_ptr is NULL, then no value is returned.
18.4.26. pthread_self - Get Thread ID#
CALLING SEQUENCE:
#include <pthread.h>
pthread_t pthread_self( void );
STATUS CODES:
The value returned is the ID of the calling thread.
DESCRIPTION:
This routine returns the ID of the calling thread.
NOTES:
NONE
18.4.27. pthread_equal - Compare Thread IDs#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_equal(
pthread_t t1,
pthread_t t2
);
STATUS CODES:
|
The thread ids are not equal. |
|
The thread ids are equal. |
DESCRIPTION:
The pthread_equal
routine is used to compare two thread IDs and determine
if they are equal.
NOTES:
The behavior is undefined if the thread IDs are not valid.
18.4.28. pthread_once - Dynamic Package Initialization#
CALLING SEQUENCE:
#include <pthread.h>
pthread_once_t once_control = PTHREAD_ONCE_INIT;
int pthread_once(
pthread_once_t *once_control,
void (*init_routine)(void)
);
STATUS CODES:
NONE
DESCRIPTION:
The pthread_once
routine is used to provide controlled initialization of
variables. The first call to pthread_once
by any thread with the same
once_control
will result in the init_routine
being invoked with no
arguments. Subsequent calls to pthread_once
with the same once_control
will have no effect.
The init_routine
is guaranteed to have run to completion when this routine
returns to the caller.
NOTES:
The behavior of pthread_once
is undefined if once_control
is automatic
storage (i.e. on a task stack) or is not initialized using
PTHREAD_ONCE_INIT
.
18.4.29. pthread_setschedparam - Set Thread Scheduling Parameters#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_setschedparam(
pthread_t thread,
int policy,
struct sched_param *param
);
STATUS CODES:
|
The scheduling parameters indicated by the parameter param is invalid. |
|
The value specified by policy is invalid. |
|
The scheduling policy was |
|
The scheduling policy was |
|
The thread indicated was invalid. |
DESCRIPTION:
The pthread_setschedparam
routine is used to set the scheduler parameters
currently associated with the thread specified by thread
to the policy
specified by policy
. The contents of param
are interpreted based upon
the policy
argument.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.30. pthread_getschedparam - Get Thread Scheduling Parameters#
CALLING SEQUENCE:
#include <pthread.h>
int pthread_getschedparam(
pthread_t thread,
int *policy,
struct sched_param *param
);
STATUS CODES:
|
The policy pointer argument is invalid. |
|
The scheduling parameters pointer argument is invalid. |
|
The thread indicated by the parameter thread is invalid. |
DESCRIPTION:
The pthread_getschedparam
routine is used to obtain the scheduler policy
and parameters associated with thread
. The current policy and associated
parameters values returned in``policy`` and param
, respectively.
NOTES:
As required by POSIX, RTEMS defines the feature symbol
_POSIX_THREAD_PRIORITY_SCHEDULING
to indicate that the family of routines
to which this routine belongs is supported.
18.4.31. pthread_getaffinity_np - Get Thread Affinity#
CALLING SEQUENCE:
#define _GNU_SOURCE
#include <pthread.h>
int pthread_getaffinity_np(
const pthread_t id,
size_t cpusetsize,
cpu_set_t *cpuset
);
STATUS CODES:
|
The cpuset pointer argument is invalid. |
|
The |
DESCRIPTION:
The pthread_getaffinity_np
routine is used to obtain the affinity.set
field from the thread control object associated with the id
. The value of
this field is returned in cpuset
.
NOTES:
NONE
18.4.32. pthread_setaffinity_np - Set Thread Affinity#
CALLING SEQUENCE:
#define _GNU_SOURCE
#include <pthread.h>
int pthread_setaffinity_np(
pthread_t id,
size_t cpusetsize,
const cpu_set_t *cpuset
);
STATUS CODES:
|
The cpuset pointer argument is invalid. |
|
The |
|
The |
|
The |
DESCRIPTION:
The pthread_setaffinity_np
routine is used to set the affinityset
field
of the thread object id
. The value of this field is returned in cpuset
NOTES:
NONE