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core.sys.posix.mqueue

D header file for Posix Message Queues
Defines external functions required to manage Posix Message Queues
mq_open(3) open a message queue mq_close(3) close a message queue mq_unlink(3) remove a message queue mq_send(3) send a message mq_receive(3) receive a message mq_timedsend(3) send a message with a timeout (linux specific) mq_timedreceive(3) receive a message with a timeout (linux specific) mq_getattr(3) get message queue attributes mq_setattr(3) set message queue attributes mq_notify(3) register asynchronous notify
License:
Boost License 1.0.
Authors:
Andreas Bok Andersen, Mathias Lang
Standards:
POSIX.1-2001.
See Also:
Standard

Source core/sys/posix/mqueue.d

alias mqd_t = int;
Message queue descriptor.
struct mq_attr;
Used in getting and setting the attributes of a message queue.
c_long mq_flags;
Message queue flags.
c_long mq_maxmsg;
Maximum number of messages.
c_long mq_msgsize;
Maximum message size.
c_long mq_curmsgs;
Number of messages currently queued.
nothrow @nogc mqd_t mq_open(const(char)* name, int oflag, ...);
Establish connection between a process and a message queue name.

Note Linux prototypes are: mqd_t mq_open (const(char)* name, int oflag); mqd_t mq_open (const(char)* name, int oflag, mode_t mode, mq_attr* attr);

Parameters:
const(char)* name Name of the message queue to open.
int oflag determines the type of access used. If O_CREAT is on oflag, the third argument is taken as a mode_t, the mode of the created message queue. If O_CREAT is on oflag, the fourth argument is taken as a pointer to a `mq_attr' (message queue attributes). If the fourth argument is null, default attributes are used.
... varargs matching the function prototypes
Returns:
Message queue descriptor or (mqd_t) -1 on error.
nothrow @nogc int mq_close(mqd_t mqdes);
Closes the message queue descriptor mqdes.
Parameters:
mqd_t mqdes Message queue descriptor to close.
Returns:
On success mq_close() returns 0; on error, -1 is returned, with errno set to indicate the error.
nothrow @nogc int mq_getattr(mqd_t mqdes, mq_attr* mqstat);
Query status and attributes of message queue mqdes.
Parameters:
mqd_t mqdes Message queue descriptor.
mq_attr* mqstat Buffer to fill with the message queue's attributes.
Returns:
On success mq_getattr() return 0; on error, -1 is returned, with errno set to indicate the error.
nothrow @nogc int mq_unlink(const(char)* name);
Remove the specified message queue name.
Parameters:
const(char)* name Name of the queue to remove.
Returns:
On success mq_unlink() returns 0; on error, -1 is returned, with errno set to indicate the error.
nothrow @nogc int mq_notify(mqd_t mqdes, const(sigevent)* notification);
Register for notification when a message is available
Parameters:
mqd_t mqdes Message queue descriptor.
const(sigevent)* notification See man 3 mq_notify for details.
Returns:
On success mq_notify() returns 0; on error, -1 is returned, with errno set to indicate the error.
nothrow @nogc ssize_t mq_receive(mqd_t mqdes, char* msg_ptr, size_t msg_len, uint* msg_prio);
Receive the oldest message with the highest priority the message queue
Parameters:
mqd_t mqdes Message queue descriptor.
char* msg_ptr Buffer to write the message to
size_t msg_len Size of the buffer provided as msg_ptr. Must be greater than the mq_msgsize attribute of the queue.
uint* msg_prio If not null, set to the priority of this message.
Returns:
On success, mq_receive() returns the number of bytes in the received message; on error, -1 is returned, with errno set to indicate the error
nothrow @nogc ssize_t mq_timedreceive(mqd_t mqdes, char* msg_ptr, size_t msg_len, uint* msg_prio, const(timespec)* abs_timeout);
Receive the oldest message with the highest priority the message queue, wait up to a certain timeout.
Parameters:
mqd_t mqdes Message queue descriptor.
char* msg_ptr Buffer to write the message to
size_t msg_len Size of the buffer provided as msg_ptr. Must be greater than the mq_msgsize attribute of the queue.
uint* msg_prio If not null, set to the priority of this message.
const(timespec)* abs_timeout Specify a ceiling on the time to block if the queue is empty.
Returns:
On success, mq_receive() returns the number of bytes in the received message; on error, -1 is returned, with errno set to indicate the error
nothrow @nogc int mq_send(mqd_t mqdes, const(char)* msg_ptr, size_t msg_len, uint msg_prio);
Add a message to a message queue.
Parameters:
mqd_t mqdes Message queue descriptor.
const(char)* msg_ptr Buffer to read the message from
size_t msg_len Size of the message provided via msg_ptr. Must be lower or equal to the mq_msgsize attribute of the queue.
uint msg_prio Priority of this message.
Returns:
On success, mq_send() return zero; on error, -1 is returned, with errno set to indicate the error.
nothrow @nogc int mq_timedsend(mqd_t mqdes, const(char)* msg_ptr, size_t msg_len, uint msg_prio, const(timespec)* abs_timeout);
Add a message to a message queue, block up to a certain time if the queue is full.
Parameters:
mqd_t mqdes Message queue descriptor.
const(char)* msg_ptr Buffer to read the message from
size_t msg_len Size of the message provided via msg_ptr. Must be lower or equal to the mq_msgsize attribute of the queue.
uint msg_prio Priority of this message.
const(timespec)* abs_timeout Specify a ceiling on the time to block if the queue is empty.
Returns:
On success, mq_timedsend() return zero; on error, -1 is returned, with errno set to indicate the error.