L4Re - L4 Runtime Environment
l4_msgtag_t Struct Reference

Message tag data structure. More...

#include <types.h>

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Public Member Functions

long label () const L4_NOTHROW
 Get the protocol value.
void label (long v) L4_NOTHROW
 Set the protocol value.
unsigned words () const L4_NOTHROW
 Get the number of untyped words.
unsigned items () const L4_NOTHROW
 Get the number of typed items.
unsigned flags () const L4_NOTHROW
 Get the flags value. More...
bool is_page_fault () const L4_NOTHROW
 Test if protocol indicates page-fault protocol.
bool is_preemption () const L4_NOTHROW
 Test if protocol indicates preemption protocol.
bool is_sys_exception () const L4_NOTHROW
 Test if protocol indicates system-exception protocol.
bool is_exception () const L4_NOTHROW
 Test if protocol indicates exception protocol.
bool is_sigma0 () const L4_NOTHROW
 Test if protocol indicates sigma0 protocol.
bool is_io_page_fault () const L4_NOTHROW
 Test if protocol indicates IO-page-fault protocol.
unsigned has_error () const L4_NOTHROW
 Test if flags indicate an error.

Data Fields

l4_mword_t raw
 raw value

Detailed Description

Message tag data structure.

Include File
#include <l4/sys/types.h>

Describes the details of an IPC operation, in particular which parts of the UTCB have to be transmitted, and also flags to enable real-time and FPU extensions.

The message tag also contains a user-defined label that could be used to specify a protocol ID. Some negative values are reserved for kernel protocols such as page faults and exceptions.

The type must be treated completely opaque.

examples/libs/l4re/c++/shared_ds/ds_srv.cc, examples/libs/l4re/streammap/server.cc, examples/sys/aliens/main.c, examples/sys/ipc/ipc_example.c, examples/sys/isr/main.c, examples/sys/singlestep/main.c, examples/sys/start-with-exc/main.c, and examples/sys/utcb-ipc/main.c.

Definition at line 159 of file types.h.

Member Function Documentation

◆ flags()

unsigned l4_msgtag_t::flags ( ) const

Get the flags value.

The flags are a combination of the flags defined by l4_msgtag_flags.

Definition at line 177 of file types.h.

Referenced by has_error(), and l4_msgtag().

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The documentation for this struct was generated from the following file: