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3 Copyright (c) 2019 Nokia
4 Copyright (c) 2018-2019 AT&T Intellectual Property.
6 Licensed under the Apache License, Version 2.0 (the "License");
7 you may not use this file except in compliance with the License.
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17 ==================================================================================
20 Mnemonic rmr_wh_send_msg_man.xfm
21 Abstract The manual page for the rmr_wh_send_msg function.
22 Author E. Scott Daniels
26 .** if formatting with tfm, the roff.im will cause roff output to be generated
27 .** if formatting with pfm, then pretty postscript will be generated
30 .im &{lib}/generic_ps.im
32 .gv e OUTPUT_RST use_rst
42 &h1(RMR Library Functions)
51 rmr_mbuf_t* rmr_wh_send_msg( void* vctx, rmr_whid_t id, rmr_mbuf_t* msg );
56 The &cw(rmr_wh_send_msg) function accepts a message buffer from the user application
57 and attempts to send it using the wormhole ID provided (id).
58 Unlike &ital(rmr_send_msg,) this function attempts to send the message directly
59 to a process at the other end of a wormhole which was created with &ital(rmr_wh-open().)
60 When sending message via wormholes, the normal RMr routing based on message type is
61 ignored, and the caller may leave the message type unspecified in the message buffer
62 (unless it is needed by the reeciving process).
65 The message buffer (msg) used to send is the same format as used for regular RMr
66 send and reply to sender operations, thus any buffer allocated by these means, or
67 calls to &ital(rmr_rcv_msg()) can be passed to this function.
71 On success, a new message buffer, with an empty payload, is returned for the application
72 to use for the next send.
73 The state in this buffer will reflect the overall send operation state and should be
77 If the state in the returned buffer is anything other than &cw(RMR_OK,) the user application
78 may need to attempt a retransmission of the message, or take other action depending on the
79 setting of &cw(errno) as described below.
82 In the event of extreme failure, a NULL pointer is returned. In this case the value of
83 &cw(errno) might be of some use, for documentation, but there will be little that the
84 user application can do other than to move on.
87 The following values may be passed back in the &ital(state) field of the returned message
91 &beg_dlist(.75i : ^&bold_font )
92 &di(RMR_ERR_WHID) The wormhole ID passed in was not associated with an open wormhole, or was out of range for a valid ID.
93 &di(RMR_ERR_NOWHOPEN) No wormholes exist, further attempt to validate the ID are skipped.
94 &di(RMR_ERR_BADARG) The message buffer pointer did not refer to a valid message.
95 &di(RMR_ERR_NOHDR) The header in the message buffer was not valid or corrupted.
99 The following values may be assigned to &cw(errno) on failure.
100 &beg_dlist(.75i : ^&bold_font )
101 &di(INVAL) Parameter(s) passed to the function were not valid, or the underlying message processing environment was unable to interpret the message.
104 &di(ENOKEY) The header information in the message buffer was invalid.
107 &di(ENXIO) No known endpoint for the message could be found.
110 &di(EMSGSIZE) The underlying transport refused to accept the message because of a size value issue (message was not attempted to be sent).
113 &di(EFAULT) The message referenced by the message buffer is corrupt (NULL pointer or bad internal length).
116 &di(EBADF) Internal RMR error; information provided to the message transport environment was not valid.
119 &di(ENOTSUP) Sending was not supported by the underlying message transport.
122 &di(EFSM) The device is not in a state that can accept the message.
125 &di(EAGAIN) The device is not able to accept a message for sending. The user application should attempt to resend.
128 &di(EINTR) The operation was interrupted by delivery of a signal before the message was sent.
131 &di(ETIMEDOUT) The underlying message environment timed out during the send process.
134 &di(ETERM) The underlying message environment is in a shutdown state.
138 The following is a simple example of how the a wormhole is created (rmr_wh_open) and then
139 how &cw(rmr_wh_send_msg) function is used to send messages.
140 Some error checking is omitted for clarity.
145 #include <rmr/rmr.h> // system headers omitted for clarity
148 rmr_whid_t whid = -1; // wormhole id for sending
149 void* mrc; //msg router context
151 rmr_mbuf_t* sbuf; // send buffer
154 mrc = rmr_init( "43086", RMR_MAX_RCV_BYTES, RMRFL_NONE );
156 fprintf( stderr, "[FAIL] unable to initialise RMr environment\n" );
160 while( ! rmr_ready( mrc ) ) { // wait for routing table info
164 sbuf = rmr_alloc_msg( mrc, 2048 );
168 whid = rmr_wh_open( mrc, "localhost:6123" ); // open fails if endpoint refuses conn
169 if( RMR_WH_CONNECTED( wh ) ) {
170 snprintf( sbuf->payload, 1024, "periodic update from sender: %d", count++ );
171 sbuf->len = strlen( sbuf->payload );
172 sbuf = rmr_wh_send_msg( mrc, whid, sbuf );