pthread_attr_setdetachstate

PTHREAD_ATTR_INIT(3)        Library Functions Manual        PTHREAD_ATTR_INIT(3)



NAME
       pthread_attr_init, pthread_attr_destroy, pthread_attr_setdetachstate,
       pthread_attr_getdetachstate, pthread_attr_setschedparam,
       pthread_attr_getschedparam, pthread_attr_setschedpolicy,
       pthread_attr_getschedpolicy, pthread_attr_setinheritsched,
       pthread_attr_getinheritsched, pthread_attr_setscope,
       pthread_attr_getscope - thread creation attributes


SYNOPSIS
       #include <pthread.h>

       int pthread_attr_init(pthread_attr_t *attr);

       int pthread_attr_destroy(pthread_attr_t *attr);

       int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate);

       int pthread_attr_getdetachstate(const pthread_attr_t *attr, int
       *detachstate);

       int pthread_attr_setschedpolicy(pthread_attr_t *attr, int policy);

       int pthread_attr_getschedpolicy(const pthread_attr_t *attr, int *policy);

       int pthread_attr_setschedparam(pthread_attr_t *attr, const struct
       sched_param *param);

       int pthread_attr_getschedparam(const pthread_attr_t *attr, struct
       sched_param *param);

       int pthread_attr_setinheritsched(pthread_attr_t *attr, int inherit);

       int pthread_attr_getinheritsched(const pthread_attr_t *attr, int
       *inherit);

       int pthread_attr_setscope(pthread_attr_t *attr, int scope);

       int pthread_attr_getscope(const pthread_attr_t *attr, int *scope);


DESCRIPTION
       Setting attributes for threads is achieved by filling a thread attribute
       object attr of type pthread_attr_t, then passing it as second argument to
       pthread_create(3).  Passing NULL is equivalent to passing a thread
       attribute object with all attributes set to their default values.

       pthread_attr_init initializes the thread attribute object attr and fills
       it with default values for the attributes. (The default values are listed
       below for each attribute.)

       Each attribute attrname (see below for a list of all attributes) can be
       individually set using the function pthread_attr_setattrname and
       retrieved using the function pthread_attr_getattrname.

       pthread_attr_destroy destroys a thread attribute object, which must not
       be reused until it is reinitialized.  pthread_attr_destroy does nothing
       in the LinuxThreads implementation.

       Attribute objects are consulted only when creating a new thread. The same
       attribute object can be used for creating several threads. Modifying an
       attribute object after a call to pthread_create does not change the
       attributes of the thread previously created.

       The following thread attributes are supported:


   detachstate
       Control whether the thread is created in the joinable state (value
       PTHREAD_CREATE_JOINABLE) or in the detached state (
       PTHREAD_CREATE_DETACHED).

       Default value: PTHREAD_CREATE_JOINABLE.

       In the joinable state, another thread can synchronize on the thread
       termination and recover its termination code using pthread_join(3), but
       some of the thread resources are kept allocated after the thread
       terminates, and reclaimed only when another thread performs
       pthread_join(3) on that thread.

       In the detached state, the thread resources are immediately freed when it
       terminates, but pthread_join(3) cannot be used to synchronize on the
       thread termination.

       A thread created in the joinable state can later be put in the detached
       thread using pthread_detach(3).


   schedpolicy
       Select the scheduling policy for the thread: one of SCHED_OTHER (regular,
       non-realtime scheduling), SCHED_RR (realtime, round-robin) or SCHED_FIFO
       (realtime, first-in first-out). See sched_setpolicy(2) for more
       information on scheduling policies.

       Default value: SCHED_OTHER.

       The realtime scheduling policies SCHED_RR and SCHED_FIFO are available
       only to processes with superuser privileges.

       The scheduling policy of a thread can be changed after creation with
       pthread_setschedparam(3).


   schedparam
       Contain the scheduling parameters (essentially, the scheduling priority)
       for the thread. See sched_setparam(2) for more information on scheduling
       parameters.

       Default value: priority is 0.

       This attribute is not significant if the scheduling policy is
       SCHED_OTHER; it only matters for the realtime policies SCHED_RR and
       SCHED_FIFO.

       The scheduling priority of a thread can be changed after creation with
       pthread_setschedparam(3).


   inheritsched
       Indicate whether the scheduling policy and scheduling parameters for the
       newly created thread are determined by the values of the schedpolicy and
       schedparam attributes (value PTHREAD_EXPLICIT_SCHED) or are inherited
       from the parent thread (value PTHREAD_INHERIT_SCHED).

       Default value: PTHREAD_EXPLICIT_SCHED.


   scope
       Define the scheduling contention scope for the created thread.  The only
       value supported in the LinuxThreads implementation is
       PTHREAD_SCOPE_SYSTEM, meaning that the threads contend for CPU time with
       all processes running on the machine. In particular, thread priorities
       are interpreted relative to the priorities of all other processes on the
       machine. The other value specified by the standard,
       PTHREAD_SCOPE_PROCESS, means that scheduling contention occurs only
       between the threads of the running process: thread priorities are
       interpreted relative to the priorities of the other threads of the
       process, regardless of the priorities of other processes.
       PTHREAD_SCOPE_PROCESS is not supported in LinuxThreads.

       Default value: PTHREAD_SCOPE_SYSTEM.


RETURN VALUE
       All functions return 0 on success and a non-zero error code on error.  On
       success, the pthread_attr_getattrname functions also store the current
       value of the attribute attrname in the location pointed to by their
       second argument.


ERRORS
       The pthread_attr_setdetachstate function returns the following error
       codes on error:

              EINVAL the specified detachstate is not one of
                     PTHREAD_CREATE_JOINABLE or PTHREAD_CREATE_DETACHED.

       The pthread_attr_setschedparam function returns the following error codes
       on error:

              EINVAL the priority specified in param is outside the range of
                     allowed priorities for the scheduling policy currently in
                     attr (1 to 99 for SCHED_FIFO and SCHED_RR; 0 for
                     SCHED_OTHER).

       The pthread_attr_setschedpolicy function returns the following error
       codes on error:

              EINVAL the specified policy is not one of SCHED_OTHER, SCHED_FIFO,
                     or SCHED_RR.


              ENOTSUP
                     policy is SCHED_FIFO or SCHED_RR, and the effective user of
                     the calling process is not super-user.

       The pthread_attr_setinheritsched function returns the following error
       codes on error:

              EINVAL the specified inherit is not one of PTHREAD_INHERIT_SCHED
                     or PTHREAD_EXPLICIT_SCHED.

       The pthread_attr_setscope function returns the following error codes on
       error:

              EINVAL the specified scope is not one of PTHREAD_SCOPE_SYSTEM or
                     PTHREAD_SCOPE_PROCESS.


              ENOTSUP
                     the specified scope is PTHREAD_SCOPE_PROCESS (not
                     supported).


AUTHOR
       Xavier Leroy <Xavier.Leroy@inria.fr>


SEE ALSO
       pthread_create(3), pthread_join(3), pthread_detach(3),
       pthread_setschedparam(3).




                                  LinuxThreads              PTHREAD_ATTR_INIT(3)