NAME
pthread_attr_getscope,
pthread_attr_setscope —
get and set the contention scope
attribute
LIBRARY
library “libpthread”
SYNOPSIS
#include
<pthread.h>
int
pthread_attr_getscope(const
pthread_attr_t * restrict attr,
int * restrict
contentionscope);
int
pthread_attr_setscope(pthread_attr_t
*attr, int
contentionscope);
DESCRIPTION
Thepthread_attr_getscope()
and
pthread_attr_setscope()
functions get and set, respectively, the contention scope attribute in the
attr object.
The contentionscope parameter specifies the scheduling contention scope of a thread. It is only possible to set the scope of a thread before the thread is created. There are two possible contention scopes:
PTHREAD_SCOPE_SYSTEM- The thread will contend for CPU resources with all other processes and threads in the system. Generally this means that the user thread is bound directly to the kernel scheduling for its entire lifetime.
PTHREAD_SCOPE_PROCESS- The thread will contend with other threads with the same scope attribute.
In general, this means that all
PTHREAD_SCOPE_PROCESSthreads are grouped together and this group of threads contends for CPU resources. This is commonly seen to require a hybrid (“M:N”) threading model in order to multiplex the user and kernel space scheduling.
Only PTHREAD_SCOPE_SYSTEM is supported in
NetBSD.
RETURN VALUES
Upon successful completion, both functions return 0. Otherwise an error number is returned to indicate the error.
ERRORS
No errors are defined for
pthread_attr_getscope().
The pthread_attr_setscope() function shall
fail if:
- [
EINVAL] - Invalid parameter.
SEE ALSO
STANDARDS
Both functions conform to ISO/IEC 9945-1:1996 (“POSIX.1”).