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pthread_attr_setscope(3)
NAME
  pthread_attr_setscope - Sets the contention scope attribute of the
  specified thread attributes object

SYNOPSIS
  #include <pthread.h>

  int pthread_attr_setscope(
	  pthread_attr_t *attr,
	  int scope );

LIBRARY
  DECthreads POSIX 1003.1c Library (libpthread.so)

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  IEEE Std 1003.1c-1995, POSIX System Application Program Interface

PARAMETERS
  attr
      Address of the thread attributes object whose contention scope
      attribute is to be modified.

  scope
      New value for the contention scope attribute of the thread attributes
      object specified by attr.

DESCRIPTION
  This routine uses the value specified in the scope argument to set the
  contention scope attribute of the thread attributes object specified in the
  attr argument.

  When creating a thread, use a thread attributes object to specify
  nondefault values for thread attributes. The contention scope attribute
  specifies the set of threads with which a thread must compete for
  processing resources.	 The contention scope attribute specifies whether the
  new thread competes for processing resources only with other threads in its
  own process, called process contention scope, or with all threads on the
  system, called system contention scope.

  On Tru64 UNIX, DECthreads supports both process contention scope and system
  contention scope threads.

  DECthreads selects at most one thread to execute on each processor at any
  point in time. DECthreads resolves the contention based on each thread's
  scheduling attributes (for example, priority) and scheduling policy (for
  example, round-robin).

  A thread created using a thread attributes object whose contention scope
  attribute is set to PTHREAD_SCOPE_PROCESS contends for processing resources
  with other threads within its own process that also were created with
  PTHREAD_SCOPE_PROCESS.  It is unspecified how such threads are scheduled
  relative to threads in other processes or threads in the same process that
  were created with PTHREAD_SCOPE_SYSTEM contention scope.

  A thread created using a thread attributes object whose contention scope
  attribute is set to PTHREAD_SCOPE_SYSTEM contends for processing resources
  with other threads in any process that also were created with
  PTHREAD_SCOPE_SYSTEM.

NOTES
  The value of the contention scope attribute of a particular thread
  attributes object does not necessarily correspond to the actual scheduling
  contention scope of any existing thread in your multithreaded program.

RETURN VALUES
  If an error condition occurs, this routine returns an integer value
  indicating the type of error. Possible return values are as follows:

  0   Successful completion.

  [EINVAL]
      The value specified by attr is not a valid thread attributes value, or
      the value specified by scope is not valid.

  [ENOTSUP]
      An attempt was made to set the attribute to an unsupported value.

ERRORS
  None

SEE ALSO
  Functions: pthread_attr_destroy(3), pthread_attr_init(3),
  pthread_attr_getscope(3), pthread_create(3)

  Manuals: Guide to DECthreads and Programmer's Guide

Index for Section 3

Alphabetical listing for P

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