pthread_attr_init Subroutine



Purpose

Creates a thread attributes object and initializes it with default
values.

Library

Threads Library (libpthreads.a)

Syntax

#include <pthread.h>

int pthread_attr_init (attr)
pthread_attr_t *attr;

Description

The pthread_attr_init subroutine creates a new thread attributes object
attr. The new thread attributes object is initialized with the following
default values:


------------------------------------------------------------------------------------------------------------------
|Always initialized                                              
                                               |
|---------------------------------------------------------------------|------------------------------------------|
|Attribute                                                       
    |Default value                             |
|---------------------------------------------------------------------|------------------------------------------|
|Detachstate                                                     
    |PTHREAD_CREATE_DETACHED                   |
------------------------------------------------------------------------------------------------------------------



------------------------------------------------------------------------------------------------------------------
|Initialized if _POSIX_THREAD_PRIORITY_SCHEDULING is defined     
                                               |
|---------------------------------------------------------------------|------------------------------------------|
|Attribute                                                       
    |Default value                             |
|---------------------------------------------------------------------|------------------------------------------|
|Contention-scope                                                
    |PTHREAD_SCOPE_PROCESS                     |
|                                                                
    |the default ensures compatibility with    |
|                                                                
    |implementations that do not support this  |
|                                                                
    |POSIX option.                             |
|---------------------------------------------------------------------|------------------------------------------|
|Inheritsched                                                    
    |PTHREAD_INHERITSCHED                      |
|---------------------------------------------------------------------|------------------------------------------|
|Schedparam                                                      
    |A sched_param structure which sched_prio  |
|                                                                
    |field is set to 1, the least favored      |
|                                                                
    |priority.                                 |
|---------------------------------------------------------------------|------------------------------------------|
|Schedpolicy                                                     
    |SCHED_OTHER                               |
------------------------------------------------------------------------------------------------------------------



------------------------------------------------------------------------------------------------------------------
|Initialized if _POSIX_THREAD_ATTR_STACKSIZE is defined          
                                               |
|---------------------------------------------------------------------|------------------------------------------|
|Attribute                                                       
    |Default value                             |
|---------------------------------------------------------------------|------------------------------------------|
|Stacksize                                                       
    |PTHREAD_STACK_MIN                         |
------------------------------------------------------------------------------------------------------------------


The default values for the thread attributes can also be retrieved
form the pthread.h header file. The following symbolic constants are
defined:

DEFAULT_DETACHSTATE	Specifies the default value for the detachstate
attribute.

DEFAULT_SCOPE	Specifies the default value for the contention-scope
attribute.

DEFAULT_INHERIT	Specifies the default value for the inheritsched attribute.

DEFAULT_PRIO	Specifies the default value for the sched_prio field
of the schedparam attribute.

DEFAULT_SCHED	Specifies the default value for the schedpolicy attribute.

Note:	The pthread.h header file must be the first included file of
each source file using the threads library.

Parameters

attr	Specifies the thread attributes object to be created.

Return Values

Upon successful completion, the new thread attributes object is filled
with default values and returned via the attr parameter, and 0 is
returned. Otherwise, an error code is returned.

Error Codes

The pthread_attr_init subroutine is unsuccessful if the following
is true:

EINVAL	The attr parameter is not valid.

ENOMEM	There is not sufficient memory to create the thread attribute
object.

Implementation Specifics

This subroutine is part of the Base Operating System (BOS) Runtime.

The priority scheduling and stack size POSIX options are implemented
in AIX.

Related Information

The pthread_attr_setdetachstate subroutine, pthread_attr_setinheritsched
subroutine, pthread_attr_setschedparam subroutine, pthread_attr_setschedpolicy
subroutine, pthread_attr_setscope subroutine, pthread_attr_setstackaddr
subroutine, pthread_attr_setstacksize subroutine, pthread_create subroutine,
pthread_attr_destroy subroutine.

Creating Threads.

Threads Library Options and Threads Library Quick Reference.