>Psychtoolbox>PsychPriority

priorityStruct = MachGetPriorityMex(policyFlavorString, defaultFlag)

OSX: ___________________________________________________________________

Retrieve current or default parameters for the main MATLAB thread for any
of the three priority flavors: ‘THREAD_STANDARD_POLICY’,
‘THREAD_TIME_CONSTRAINT_POLICY’ and ‘THREAD_PRECEDENCE_POLICY’

The returned struct contains these fields:

priorityStruct.threadID
a number identifying the current thread.

priorityStruct.flavor
one of: ‘THREAD_STANDARD_POLICY’, ‘THREAD_TIME_CONSTRAINT_POLICY’,
‘THREAD_PRECEDENCE_POLICY’

priorityStruct.policy
see policy struct variants below

priorityStruct.policySize
The amount of memory allocated for the policy struct passed to the
Mach function thread_policy_get() by MachGetPriorityMex.

priorityStruct.policyFillSize
amount of memory filled into the policy struct by
Mach function thread_policy_get().

priorityStruct.getDefault
value of the defaultFlag argument passed into MachGetPriorityMex.

priorityStruct.isDefault
If the flag value passed to MachGetPriorityMex is 0, requesting
current parameter values and not default parameter values and yet
MachGetPriorityMex returns default parameters and defaultFlag value
1, then the priority flavor which was specified in the first
argument to priorityFlavorString is not in effect.

The form of the embedded struct “policy” depends on the value of
priorityFlavorString argument.

‘THREAD_STANDARD_POLICY’:
priorityStruct.flavorPolicy.no_data % a place holder only

‘THREAD_TIME_CONSTRAINT_POLICY’ % see help MachSetTimeConstraintPriority
priorityStruct.flavorPolicy.period
priorityStruct.flavorPolicy.computation
priorityStruct.flavorPolicy.constraint
priorityStruct.flavorPolicy.preemptible

‘THREAD_PRECEDENCE_POLICY’ % see help MachSetTimeConstraintPriority
priorityStruct.flavorPolicy.importance

There are three policy flavors but a thread may have only one of two
policy modes: THREAD_STANDARD_POLICY or THREAD_TIME_CONSTRAINT_POLICY.
These are mutually-exclusive modes; setting a thread to either one will
unset the other mode. The “importance” parameter associated with
THREAD_PRECEDENCE_POLICY is preserved after either THREAD_STANDARD_POLICY
or THREAD_TIME_CONSTRAINT_POLICY is set, however the
THREAD_PRECEDENCE_POLICY “importance” setting is ignored by the Mach task
scheduler while a thread is in THREAD_TIME_CONSTRAINT_POLICY mode. A
thread is governed by the “importance” parameter only when in
THREAD_STANDARD_POLICY mode.

MachGetPriorityMex uses the OS X Darwin function thread_policy_get().
For more information on thread_policy_get() see:
Psychtoolbox3/Source/Common/MachPriorityMex/MachGetPriorityMex.c
http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgramming/scheduler/chapter_8_section_4.html
/usr/include/mach/thread_policy.h

OS9: ___________________________________________________________________

MachGetPriorityMex does not exist in OS 9.

WIN: ________________________________________________________________

MachGetPriorityMex does not exist in Windows.

_________________________________________________________________________

see also: Priority, Rush, MachGetPriorityFlavor, MachSetPriorityMex,