mirror of https://gitee.com/bigwinds/arangodb
158 lines
4.2 KiB
Plaintext
158 lines
4.2 KiB
Plaintext
zframe(7)
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=========
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NAME
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----
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zframe - working with single message frames
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SYNOPSIS
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--------
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----
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#define ZFRAME_MORE 1
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#define ZFRAME_REUSE 2
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// Create a new frame with optional size, and optional data
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zframe_t *
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zframe_new (const void *data, size_t size);
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// Destroy a frame
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void
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zframe_destroy (zframe_t **self_p);
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// Receive frame from socket, returns zframe_t object or NULL if the recv
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// was interrupted. Does a blocking recv, if you want to not block then use
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// zframe_recv_nowait().
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zframe_t *
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zframe_recv (void *socket);
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// Receive a new frame off the socket. Returns newly allocated frame, or
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// NULL if there was no input waiting, or if the read was interrupted.
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zframe_t *
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zframe_recv_nowait (void *socket);
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// Send a frame to a socket, destroy frame after sending
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void
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zframe_send (zframe_t **self_p, void *socket, int flags);
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// Return number of bytes in frame data
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size_t
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zframe_size (zframe_t *self);
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// Return address of frame data
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byte *
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zframe_data (zframe_t *self);
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// Create a new frame that duplicates an existing frame
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zframe_t *
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zframe_dup (zframe_t *self);
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// Return frame data encoded as printable hex string
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char *
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zframe_strhex (zframe_t *self);
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// Return frame data copied into freshly allocated string
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char *
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zframe_strdup (zframe_t *self);
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// Return TRUE if frame body is equal to string, excluding terminator
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Bool
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zframe_streq (zframe_t *self, char *string);
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// Return frame 'more' property
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int
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zframe_more (zframe_t *self);
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// Return TRUE if two frames have identical size and data
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// If either frame is NULL, equality is always false.
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Bool
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zframe_eq (zframe_t *self, zframe_t *other);
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// Print contents of frame to stderr
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void
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zframe_print (zframe_t *self, char *prefix);
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// Set new contents for frame
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void
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zframe_reset (zframe_t *self, const void *data, size_t size);
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// Self test of this class
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int
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zframe_test (Bool verbose);
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----
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DESCRIPTION
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-----------
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The zframe class provides methods to send and receive single message
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frames across 0MQ sockets. A 'frame' corresponds to one zmq_msg_t. When
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you read a frame from a socket, the zframe_more() method indicates if the
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frame is part of an unfinished multipart message. The zframe_send method
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normally destroys the frame, but with the ZFRAME_REUSE flag, you can send
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the same frame many times. Frames are binary, and this class has no
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special support for text data.
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EXAMPLE
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-------
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.From zframe_test method
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----
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zctx_t *ctx = zctx_new ();
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void *output = zsocket_new (ctx, ZMQ_PAIR);
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zsocket_bind (output, "inproc://zframe.test");
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void *input = zsocket_new (ctx, ZMQ_PAIR);
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zsocket_connect (input, "inproc://zframe.test");
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// Send five different frames, test ZFRAME_MORE
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int frame_nbr;
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for (frame_nbr = 0; frame_nbr < 5; frame_nbr++) {
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zframe_t *frame = zframe_new ("Hello", 5);
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zframe_send (&frame, output, ZFRAME_MORE);
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}
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// Send same frame five times, test ZFRAME_REUSE
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zframe_t *frame = zframe_new ("Hello", 5);
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for (frame_nbr = 0; frame_nbr < 5; frame_nbr++) {
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zframe_send (&frame, output, ZFRAME_MORE + ZFRAME_REUSE);
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}
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assert (frame);
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zframe_t *copy = zframe_dup (frame);
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assert (zframe_eq (frame, copy));
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zframe_destroy (&frame);
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assert (!zframe_eq (frame, copy));
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assert (zframe_size (copy) == 5);
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zframe_destroy (©);
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assert (!zframe_eq (frame, copy));
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// Send END frame
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frame = zframe_new ("NOT", 3);
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zframe_reset (frame, "END", 3);
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char *string = zframe_strhex (frame);
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assert (streq (string, "454E44"));
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free (string);
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string = zframe_strdup (frame);
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assert (streq (string, "END"));
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free (string);
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zframe_send (&frame, output, 0);
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// Read and count until we receive END
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frame_nbr = 0;
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for (frame_nbr = 0;; frame_nbr++) {
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zframe_t *frame = zframe_recv (input);
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if (zframe_streq (frame, "END")) {
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zframe_destroy (&frame);
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break;
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}
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assert (zframe_more (frame));
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zframe_destroy (&frame);
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}
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assert (frame_nbr == 10);
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frame = zframe_recv_nowait (input);
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assert (frame == NULL);
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zctx_destroy (&ctx);
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----
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SEE ALSO
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--------
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linkczmq:czmq[7]
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