Setting the Scope

Use pthread_attr_setscope(3C) to establish the contention scope of a thread, either PTHREAD_SCOPE_SYSTEM or PTHREAD_SCOPE_PROCESS. With PTHREAD_SCOPE_SYSTEM, this thread contends with all threads in the system. With PTHREAD_SCOPE_PROCESS , this thread contends with other threads in the process.

pthread_attr_setscope Syntax

int pthread_attr_setscope(pthread_attr_t *tattr,int scope);

#include <pthread.h>

pthread_attr_t tattr;
int ret;

/* bound thread */
ret = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM);

/* unbound thread */
ret = pthread_attr_setscope(&tattr, PTHREAD_SCOPE_PROCESS);

This example uses three function calls: a call to initialize the attributes, a call to set any variations from the default attributes, and a call to create the pthreads.

#include <pthread.h>

pthread_attr_t attr;
pthread_t tid;
void *start_routine(void *);
void *arg;
int ret;

/* initialized with default attributes */
ret = pthread_attr_init (&tattr);

ret =  pthread_attr_setscope(&tattr, PTHREAD_SCOPE_SYSTEM);
ret = pthread_create (&tid, &tattr, start_routine, arg);

pthread_attr_setscope Return Values

pthread_attr_setscope() returns zero after completing successfully. Any other return value indicates that an error occurred. If the following conditions occur, the function fails and returns the corresponding value.

Description: An attempt was made to set tattr to a value that is not valid.