mach_msg_descriptor

Structure - Specifies operations that must be performed on a given IPC message element.

SYNOPSIS

typedef struct
{
       void*                             pad1;
       mach_msg_size_t                   pad2;
       unsigned int                      pad3 : 24;
       mach_msg_descriptor_type_t        type : 8;
} mach_msg_type_descriptor_t;

typedef struct
{
       mach_port_t                       name;
       mach_msg_size_t                   pad1;
       unsigned int                      pad2 : 16;
       mach_msg_type_name_t       disposition : 8;
       mach_msg_descriptor_type_t        type : 8;
} mach_msg_port_descriptor_t;

typedef struct
{
       void*                          address;
       mach_msg_size_t                   size;
       boolean_t                   deallocate : 8;
       mach_msg_copy_options_t           copy : 8;
       unsigned int                      pad1 : 8;
       mach_msg_descriptor_type_t        type : 8;
} mach_msg_ool_descriptor_t;

typedef struct
{
       void*                           address;
       mach_msg_size_t                   count;
       boolean_t                    deallocate : 8;
       mach_msg_copy_options_t            copy : 8;
       mach_msg_type_name_t        disposition : 8;
       mach_msg_descriptor_type_t         type : 8;
} mach_msg_ool_ports_descriptor_t;

typedef union
{
       mach_msg_port_descriptor_t             port;
       mach_msg_ool_descriptor_t       out_of_line;
       mach_msg_ool_ports_descriptor_t   ool_ports;
       mach_msg_type_descriptor_t             type;
} mach_msg_descriptor_t;

FIELDS

name

For single port descriptors, the name of the port whose right is being sent.

disposition

For single port or out-of-line port array descriptors, the IPC processing to be done for the rights for the named ports.

address

For out-of-line data or port array descriptors, the address of the out-of-line data or port (name) array.

size

For out-of-line data descriptors, the size of the out-of-line region, in bytes.

deallocate

For out-of-line data descriptors, true if the set of pages containing the array should be de-allocated when the message is sent.

copy

For out-of-line descriptors, a description of the method by which the data should be copied.

count

For out-of-line port array descriptors, the number of port names in the array.

type

For any type of descriptor, the type of descriptor.

port

A descriptor that describes a single port right.

out_of_line

A descriptor that describes an out-of-line data array.

ool_ports

A descriptor that describes an out-of-line port array.

DESCRIPTION

A mach_msg_descriptor structure describes the processing to be performed for an element of kernel-processed data in a Mach message.

RELATED INFORMATION

Functions: mach_msg.

Data Structures: mach_msg_header.