mach_ports_register.html [plain text]
<strong>Function</strong> - Register an array of well-known ports on behalf of the target task.
[in task send right]
The task for which the ports are to be registered.
[in pointer to array of registered send rights]
The array of ports to
The number of ports in the array. Note that while this is a
variable, the kernel accepts only a limited number of ports. The
maximum number of ports is defined by the global constant
The <strong>mach_ports_register</strong> function registers an array
of well-known system
ports for the specified task. The task holds only send rights
for the registered
ports. The valid well-known system ports are:
The port for the Name Server
The port for the Environment Manager
The port for the Service server
Each port must be placed in a specific slot in the array. The slot numbers are
defined (in <strong>mach.h</strong>) by the global constants <strong>NAME_SERVER_SLOT</strong>,
<strong>ENVIRONMENT_SLOT</strong>, and <strong>SERVICE_SLOT</strong>.
A task can retrieve the currently registered ports by using the
When a new task is created (with <strong>task_create</strong>),
the child task can inherit the
parent's registered ports. Note that child tasks do not automatically
to these ports. They must use <strong>mach_ports_lookup</strong> to
get them. It is intended
that port registration be used only for task initialization, and then only by
run-time support modules.
A parent task has three choices when passing registered ports to child tasks:
The parent task can do nothing. In this case, all child tasks
inherit access to
the same ports that the parent has.
The parent task can use <strong>mach_ports_register</strong> to modify
its set of registered
ports before creating child tasks. In this case, the child tasks get access
modified set of ports. After creating its child tasks. the parent can use
<strong>mach_ports_register</strong> again to reset its registered ports.
The parent task can first create a specific child task and then use
<strong>mach_ports_register</strong> to modify the child's inherited
set of ports, before starting
the child's thread(s). The parent must specify the child's task port, rather
than its own, on the call to <strong>mach_ports_register</strong>.
Tasks other than the Name Server and the Environment Manager
should not need access to the Service port. The Name Server port is
the same for all tasks on a given machine. The Environment port
is the only port
likely to have different values for different tasks.
Registered ports are restricted to those ports that are used by the run-time
system to initialize a task. A parent task can pass other ports
to its child tasks
An initial message (see <strong>mach_msg</strong>).
The Name Server, for public ports.
The Environment Manager, for private ports.
The task bootstrap port (see <strong>task_get_special_port</strong>).
Only generic errors apply.