NAME    [Toc]    [Back]

       pthread_attr_setscope   -   Sets   the   contention  scope
       attribute of the specified thread attributes object

SYNOPSIS    [Toc]    [Back]

       #include <pthread.h>

       int pthread_attr_setscope(
               pthread_attr_t *attr,
               int scope );

LIBRARY    [Toc]    [Back]

       DECthreads POSIX 1003.1c Library (libpthread.so)

STANDARDS    [Toc]    [Back]

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

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

PARAMETERS    [Toc]    [Back]

       Address of the thread attributes object  whose  contention
       scope attribute is to be modified.  New value for the contention
 scope attribute of the  thread  attributes  object
       specified by attr.

DESCRIPTION    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       If an error condition  occurs,  this  routine  returns  an
       integer  value  indicating  the  type  of  error. Possible
       return values are as follows: Successful completion.   The
       value  specified  by attr is not a valid thread attributes
       value, or the value specified by scope is not  valid.   An
       attempt  was  made  to set the attribute to an unsupported
       value.

ERRORS    [Toc]    [Back]

       None

SEE ALSO    [Toc]    [Back]

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

       Manuals: Guide to DECthreads and Programmer's Guide



                                         pthread_attr_setscope(3)