pthread_attr_setscope - Sets the contention scope attribute of the specified thread attributes object.
DECthreads POSIX 1003.1c Library (libpthread.so)
Interfaces documented on this reference page conform to industry standards as follows:
IEEE Std 1003.1c-1995, POSIX System Application Program Interface
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.
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. The specified attributes object must already be initialized at the time this routine is called.
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 <NEWTERM>(process contention scope), or with all threads on the system, called <NEWTERM>(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.
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.
If an error condition occurs, this routine returns an integer value indicating the type of error. Possible return values are as follows: Successful completion. This routine is not supported by the implementation. The value of the attribute being set is not valid. An attempt was made to set the attribute to an unsupported value.
Functions: pthread_attr_destroy(3), pthread_attr_init(3), pthread_attr_getscope(3), pthread_create(3)
Manuals: Guide to DECthreads and Programmer's Guide delim off