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mirror of https://github.com/zeromq/libzmq.git synced 2024-12-26 23:01:04 +08:00

more man pages filled in

This commit is contained in:
Martin Sustrik 2009-11-22 16:51:21 +01:00
parent 6602cce9af
commit e90ada0d04
11 changed files with 368 additions and 3 deletions

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@ -180,7 +180,7 @@ ZMQ_EXPORT int zmq_term (void *context);
// Socket to send requests and receive replies. Requests are
// load-balanced among all the peers. This socket type allows
// only an alternated sequence of send's and recv's
// only an alternated sequence of send's and recv's.
#define ZMQ_REQ 3
// Socket to receive requests and send replies. This socket type allows

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@ -4,9 +4,45 @@ zmq_bind \- binds the socket to the specified address
.SH SYNOPSIS
.B int zmq_bind (void *s, const char *addr);
.SH DESCRIPTION
The function binds socket
.IR s to a particular transport. Actual semantics of the
command depend on the underlying transport mechanism, however, in cases where
peers connect in an asymetric manner,
.IR zmq_bind
should be called first,
.IR zmq_connect
afterwards. For actual formats of
.IR addr
parameter for different types of transport have a look at
.IR zmq(7) .
Note that single socket can be bound (and connected) to
arbitrary number of peers using different transport mechanisms.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
.IP "\fBEPROTONOSUPPORT\fP"
unsupported protocol.
.IP "\fBENOCOMPATPROTO\fP"
protocol is not compatible with the socket type.
.IP "\fBEADDRINUSE\fP"
the given address is already in use.
.IP "\fBEADDRNOTAVAIL\fP"
a nonexistent interface was requested or the requested address was not local.
.SH EXAMPLE
.nf
void *s = zmq_socket (context, ZMQ_PUB);
assert (s);
int rc = zmq_bind (s, "inproc://my_publisher");
assert (rc == 0);
rc = zmq_bind (s, "tcp://eth0:5555");
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_connect (3)
.BR zmq_socket (3)
.BR zmq (7)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -4,9 +4,24 @@ zmq_close \- destroys 0MQ socket
.SH SYNOPSIS
.B int zmq_close (void *s);
.SH DESCRIPTION
Destroys 0MQ socket (one created using
.IR zmq_socket
function). All sockets have to be properly closed before the application
terminates, otherwise memory leaks will occur.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
No errors are defined.
.SH EXAMPLE
.nf
int rc = zmq_close (s);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_socket (3)
.BR zmq_term (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -1,12 +1,47 @@
.TH zmq_connect 3 "" "(c)2007-2009 FastMQ Inc." "0MQ User Manuals"
.SH NAME
zmq_connect \- connects the socket to the specified address
zmq_connect \- connect the socket to the specified peer
.SH SYNOPSIS
.B int zmq_connect (void *s, const char *addr);
.SH DESCRIPTION
The function connect socket
.IR s to the peer identified by
.IR addr .
Actual semantics of the command depend on the underlying transport mechanism,
however, in cases where peers connect in an asymetric manner,
.IR zmq_bind
should be called first,
.IR zmq_connect
afterwards. For actual formats of
.IR addr
parameter for different types of transport have a look at
.IR zmq(7) .
Note that single socket can be connected (and bound) to
arbitrary number of peers using different transport mechanisms.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
.IP "\fBEPROTONOSUPPORT\fP"
unsupported protocol.
.IP "\fBENOCOMPATPROTO\fP"
protocol is not compatible with the socket type.
.IP "\fBECONNREFUSED\fP"
no-one listening on the remote address.
.SH EXAMPLE
.nf
void *s = zmq_socket (context, ZMQ_SUB);
assert (s);
int rc = zmq_connect (s, "inproc://my_publisher");
assert (rc == 0);
rc = zmq_connect (s, "tcp://server001:5555");
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_bind (3)
.BR zmq_socket (3)
.BR zmq (7)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -4,9 +4,34 @@ zmq_flush \- flushes pre-sent messages to the socket
.SH SYNOPSIS
.B int zmq_flush (void *s);
.SH DESCRIPTION
Flushes all the pre-sent messages - i.e. those that have been sent with
ZMQ_NOFLUSH flag - to the socket. This functionality improves performance in
cases where several messages are sent during a single business operation.
It should not be used as a transaction - ACID properties are not guaranteed.
Note that calling
.IR zmq_send
without ZMQ_NOFLUSH flag automatically flushes all previously pre-sent messages.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
.IP "\fBENOTSUP\fP"
function isn't supported by particular socket type.
.IP "\fBEFSM\fP"
function cannot be called at the moment, because socket is not in the
approprite state.
.SH EXAMPLE
.nf
rc = zmq_send (s, &msg1, ZMQ_NOFLUSH);
assert (rc == 0);
rc = zmq_send (s, &msg2, ZMQ_NOFLUSH);
assert (rc == 0);
rc = zmq_flush (s);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_send (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -25,7 +25,7 @@ Function returns context handle is successful. Otherwise it returns NULL and
sets errno to one of the values below.
.SH ERRORS
.IP "\fBEINVAL\fP"
- there's less than one application thread allocated, or number of I/O threads
there's less than one application thread allocated, or number of I/O threads
is negative.
.SH EXAMPLE
.nf
@ -34,5 +34,6 @@ assert (ctx);
.fi
.SH SEE ALSO
.BR zmq_term (3)
.BR zmq_socket (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -4,9 +4,49 @@ zmq_recv \- retrieves a message from the socket
.SH SYNOPSIS
.B int zmq_recv (void *s, zmq_msg_t *msg, int flags);
.SH DESCRIPTION
Receive a message from the socket
.IR s ,
store it in
.IR msg .
Any content previously in
.IR msg
will be properly deallocated.
.IR flags
argument can be combination of the flags described below.
.IP "\fBZMQ_NOBLOCK\fP"
The flag specifies that the operation should be performed in
non-blocking mode. I.e. if it cannot be processed immediately,
error should be returned with
.IR errno
set to EAGAIN.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
.IP "\fBEAGAIN\fP"
it's a non-blocking receive and there's no message available at the moment.
.IP "\fBENOTSUP\fP"
function isn't supported by particular socket type.
.IP "\fBEFSM\fP"
function cannot be called at the moment, because socket is not in the
approprite state. This error may occur with sockets that switch between
several states (e.g. ZMQ_REQ).
.SH EXAMPLE
.nf
zmq_msg_t msg;
int rc = zmq_msg_init (&msg);
assert (rc == 0);
rc = zmq_recv (s, &msg, 0);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_send (3)
.BR zmq_msg_init (3)
.BR zmq_msg_data (3)
.BR zmq_msg_size (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -4,9 +4,61 @@ zmq_send \- sends a message
.SH SYNOPSIS
.B int zmq_send (void *s, zmq_msg_t *msg, int flags);
.SH DESCRIPTION
Send the message
.IR msg
to the socket
.IR s .
.IR flags
argument can be combination the flags described below.
.IP "\fBZMQ_NOBLOCK\fP"
The flag specifies that the operation should be performed in
non-blocking mode. I.e. if it cannot be processed immediately,
error should be returned with
.IR errno
set to EAGAIN.
.IP "\fBZMQ_NOFLUSH\fP"
The flag specifies that
.IR zmq_send
should not flush the message downstream immediately. Instead, it should batch
ZMQ_NOFLUSH messages and send them downstream only once
.IR zmq_flush
is invoked. This is an optimisation for cases where several messages are sent
in a single business transaction. However, the effect is measurable only in
extremely high-perf scenarios (million messages a second or so).
If that's not your case, use standard flushing send instead.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
.IP "\fBEAGAIN\fP"
it's a non-blocking send and message cannot be sent at the moment.
.IP "\fBENOTSUP\fP"
function isn't supported by particular socket type.
.IP "\fBEFSM\fP"
function cannot be called at the moment, because socket is not in the
approprite state. This error may occur with sockets that switch between
several states (e.g. ZMQ_REQ).
.SH EXAMPLE
.nf
zmq_msg_t msg;
int rc = zmq_msg_init_size (&msg, 6);
assert (rc == 0);
memset (zmq_msg_data (&msg), 'A', 6);
rc = zmq_send (s, &msg, 0);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_flush (3)
.BR zmq_recv (3)
.BR zmq_msg_init (3)
.BR zmq_msg_init_size (3)
.BR zmq_msg_init_data (3)
.BR zmq_msg_data (3)
.BR zmq_msg_size (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -4,9 +4,112 @@ zmq_setsockopt \- sets a specified option on a 0MQ socket
.SH SYNOPSIS
.B int zmq_setsockopt (void *s, int option, const void *optval, size_t optvallen);
.SH DESCRIPTION
Sets an option on the socket.
.IR option
argument specifies the option from the list below.
.IR optval
is a pointer to the value to set,
.IR optvallen
is the size of the value in bytes.
.IP "\fBZMQ_HWM\fP"
High watermark for the message pipes associated with the socket. The water
mark cannot be exceeded. If the messages don't fit into the pipe emergency
mechanisms of the particular socket type are used (block, drop etc.) If HWM
is set to zero, there are no limits for the content of the pipe.
Type: int64_t Unit: bytes Default: 0
.IP "\fBZMQ_LWM\fP"
Low watermark makes sense only if high watermark is defined (i.e. is non-zero).
When the emergency state is reached when messages overflow the pipe, the
emergency lasts till the size of the pipe decreases to low watermark.
At that point normal state is resumed.
Type: int64_t Unit: bytes Default: 0
.IP "\fBZMQ_SWAP\fP"
Swap allows the pipe to exceed high watermark. However, the data are written
to the disk rather than held in the memory. Until high watermark is
exceeded there is no disk activity involved though. The value of the option
defines maximal size of the swap file.
Type: int64_t Unit: bytes Default: 0
.IP "\fBZMQ_AFFINITY\fP"
Affinity defines which threads in the thread pool will be used to handle
newly created sockets. This way you can dedicate some of the threads (CPUs)
to a specific work. Value of 0 means no affinity. Work is distributed
fairly among the threads in the thread pool. For non-zero values, the lowest
bit corresponds to the thread 1, second lowest bit to the thread 2 etc.
Thus, value of 3 means that from now on newly created sockets will handle
I/O activity exclusively using threads no. 1 and 2.
Type: int64_t Unit: N/A (bitmap) Default: 0
.IP "\fBZMQ_IDENTITY\fP"
Identity of the socket. Identity is important when restarting applications.
If the socket has no identity, each run of the application is completely
separated from other runs. However, with identity application reconnects to
existing infrastructure left by the previous run. Thus it may receive
messages that were sent in the meantime, it shares pipe limits with the
previous run etc.
Type: string Unit: N/A Default: NULL
.IP "\fBZMQ_SUBSCRIBE\fP"
Applicable only to ZMQ_SUB socket type. It establishes new message filter.
When ZMQ_SUB socket is created all the incoming messages are filtered out.
This option allows you to subscribe for all messages ("*"), messages with
specific topic ("x.y.z") and/or messages with specific topic prefix
("x.y.*"). Topic is one-byte-size-prefixed string located at
the very beginning of the message. Multiple filters can be attached to
a single 'sub' socket. In that case message passes if it matches at least
one of the filters.
Type: string Unit: N/A Default: N/A
.IP "\fBZMQ_UNSUBSCRIBE\fP"
Applicable only to ZMQ_SUB socket type. Removes existing message filter.
The filter specified must match the string passed to ZMQ_SUBSCRIBE options
exactly. If there were several instances of the same filter created,
this options removes only one of them, leaving the rest in place
and functional.
Type: string Unit: N/A Default: N/A
.IP "\fBZMQ_RATE\fP"
This option applies only to sending side of multicast transports (pgm & udp).
It specifies maximal outgoing data rate that an individual sender socket
can send.
Type: uint64_t Unit: kilobits/second Default: 100
.IP "\fBZMQ_RECOVERY_IVL\fP"
This option applies only to multicast transports (pgm & udp). It specifies
how long can the receiver socket survive when the sender is inaccessible.
Keep in mind that large recovery intervals at high data rates result in
very large recovery buffers, meaning that you can easily overload your box
by setting say 1 minute recovery interval at 1Gb/s rate (requires
7GB in-memory buffer).
Type: uint64_t Unit: seconds Default: 10
.IP "\fBZMQ_MCAST_LOOP\fP"
This option applies only to multicast transports (pgm & udp). Value of 1
means that the mutlicast packets can be received on the box they were sent
from. Setting the value to 0 disables the loopback functionality which
can have negative impact on the performance. If possible, disable
the loopback in production environments.
Type: uint64_t Unit: N/A (boolean value) Default: 1
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
.IP "\fBEINVAL\fP"
unknown option, a value with incorrect length or invalid value.
.SH EXAMPLE
.nf
int rc = zmq_setsockopt (s, ZMQ_SUBSCRIBE, "*", 1);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_socket (3)
.BR zmq (7)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -4,9 +4,65 @@ zmq_socket \- creates 0MQ socket
.SH SYNOPSIS
.B void *zmq_socket (void *context, int type);
.SH DESCRIPTION
Open a socket within the specified
.IR context .
To create a context, use
.IR zmq_init
function.
.IR type
argument can be one of the values defined below. Note that each socket is owned
by exactly one thread (the one that it was created from) and should not be used
from any other thread.
.IP "\fBZMQ_P2P\fP"
Socket to communicate with a single peer. Allows for only a single connect or a
single bind. There's no message routing or message filtering involved.
.IP "\fBZMQ_PUB\fP"
Socket to distribute data. Recv fuction is not implemented for this socket
type. Messages are distributed in fanout fashion to all the peers.
.IP "\fBZMQ_SUB\fP"
Socket to subscribe for data. Send function is not implemented for this
socket type. Initially, socket is subscribed for no messages. Use ZMQ_SUBSCRIBE
option to specify which messages to subscribe for.
.IP "\fBZMQ_REQ\fP"
Socket to send requests and receive replies. Requests are load-balanced among
all the peers. This socket type allows only an alternated sequence of
send's and recv's.
.IP "\fBZMQ_REP\fP"
Socket to receive requests and send replies. This socket type allows
only an alternated sequence of recv's and send's. Each send is routed to
the peer that issued the last received request.
.SH RETURN VALUE
Function returns socket handle is successful. Otherwise it returns NULL and
sets errno to one of the values below.
.SH ERRORS
.IP "\fBEINVAL\fP"
invalid socket type.
.IP "\fBEMTHREAD\fP"
the number of application threads allowed to own 0MQ sockets was exceeded. See
.IR app_threads
parameter to
.IR zmq_init
function.
.SH EXAMPLE
.nf
void *s = zmq_socket (context, ZMQ_PUB);
assert (s);
int rc = zmq_bind (s, "tcp://192.168.0.1:5555");
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_init (3)
.BR zmq_setsockopt (3)
.BR zmq_bind (3)
.BR zmq_connect (3)
.BR zmq_send (3)
.BR zmq_flush (3)
.BR zmq_recv (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>

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@ -19,5 +19,7 @@ int rc = zmq_term (context);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_init (3)
.BR zmq_close (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>