Perimeter options

Several flags are used to specify the perimeters. These flags fall into three categories:

• Define the presence and scope of the inner perimeter.

• Define the presence of the outer perimeter (which can have only one scope).

• Modify the default concurrency for the different entry points.

The inner perimeter is controlled by these mutually exclusive flags:

• D_MTPERMOD: The module has an inner perimeter that encloses all the module's queues.

• D_MTAPAIR: The module has an inner perimeter around each read/write pair of queues.

• D_MTPERQ: The module has an inner perimeter around each queue.

• None of the above: The module has no inner perimeter.

The presence of the outer perimeter is configured using:

• D_MTOUTEPERIM: In addition to any inner perimeter (or none), the module has an outer perimeter that encloses all the module's queues. This can be combined with all the inner perimeter options except D_MTPERMOD.

Recall that by default all synchronous entry points enter the inner perimeter exclusively and enter the outer perimeter shared. This behavior can be modified in two ways:

• D_MTOCEXCL: The framework invokes the open and close procedures with exclusive access at the outer perimeter (instead of the default shared access at the outer perimeter.)

• D_MTPUTSHARED: The framework invokes the put procedures with shared access at the inner perimeter (instead of the default exclusive access at the inner perimeter).