.if false
==================================================================================
- Copyright (c) 2019 Nokia
- Copyright (c) 2018-2019 AT&T Intellectual Property.
+ Copyright (c) 2019-2020 Nokia
+ Copyright (c) 2018-2020 AT&T Intellectual Property.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
==================================================================================
.fi
.if false
- Mnemonic rmr_send_msg_man.xfm
- Abstract The manual page for the rmr_send_msg function.
- Author E. Scott Daniels
- Date 28 January 2019
+ Mnemonic rmr_send_msg_man.xfm
+ Abstract The manual page for the rmr_send_msg function.
+ Author E. Scott Daniels
+ Date 28 January 2019
.fi
.gv e LIB lib
-.im &{lib}/man/setup.im
+.im &{lib}/man/setup.im
&line_len(6i)
&h1(RMR Library Functions)
&h2(NAME)
- rmr_send_msg
+ rmr_send_msg
&h2(SYNOPSIS )
&indent
&uindent
&h2(DESCRIPTION)
-The &cw(rmr_send_msg) function accepts a message buffer from the user application
+The &cw(rmr_send_msg) function accepts a message buffer from the user application
and attempts to send it.
The destination of the message is selected based on the message type specified
in the message buffer, and the matching information in the routing tables
-which are currently in use by the RMR library.
+which are currently in use by the RMR library.
This may actually result in the sending of the message to multiple destinations
-which could degrade expected overall performance of the user application.
+which could degrade expected overall performance of the user application.
(Limiting excessive sending of messages is the responsibility of the application(s)
-responsible for building the routing table used by the RMR library, and not the
+responsible for building the routing table used by the RMR library, and not the
responsibility of the library.)
.** pull in common retry text
-.im &{lib}/man/retry.im
+.im &{lib}/man/retry.im
&h2(RETURN VALUE)
On success, a new message buffer, with an empty payload, is returned for the application
to use for the next send.
-The state in this buffer will reflect the overall send operation state and should be
-&cw(RMR_OK.)
+The state in this buffer will reflect the overall send operation state and will be
+&cw(RMR_OK) when the send was successful.
&space
-When the message cannot be successfully sent this function will return the unsent (original)
-message buffer with the state set to indicate the reason for failure.
+When the message cannot be successfully sent this function will return the unsent (original)
+message buffer with the state set to indicate the reason for failure.
The value of &ital(errno) may also be set to reflect a more detailed failure reason if it
is known.
&space
-In the event of extreme failure, a NULL pointer is returned. In this case the value of
-&cw(errno) might be of some use, for documentation, but there will be little that the
+In the event of extreme failure, a nil pointer is returned. In this case the value of
+&cw(errno) might be of some use, for documentation, but there will be little that the
user application can do other than to move on.
+.sp 1
+&bold(CAUTION^:)
+In some cases it is extremely likely that the message returned by the send function
+does &bold(not) reference the same memory structure.
+Thus is important for the user programme to capture the new pointer for future use
+or to be passed to &cw(rmr_free().)
+If you are experiencing either double free errors or segment faults in either &cw(rmr_free()) or
+&cw(rmr_send_msg(),) ensure that the return value from this function is being captured
+and used.
+
&h2(ERRORS)
The following values may be passed back in the &ital(state) field of the returned message
-buffer.
+buffer.
&space
&beg_dlist(.75i : ^&bold_font )
-&di(RMR_RETRY) The message could not be sent, but the underlying transport mechanism
- indicates that the failure is temporary. If the send operation is tried again
- it might be successful.
-&di(RMR_SEND_FAILED) The send operation was not successful and the underlying transport
- mechanism indicates a permanent (hard) failure; retrying the send is not possible.
-&di(RMR_ERR_BADARG) The message buffer pointer did not refer to a valid message.
-&di(RMR_ERR_NOHDR) The header in the message buffer was not valid or corrupted.
-&di(RMR_ERR_NOENDPT) The message type in the message buffer did not map to a known endpoint.
+&ditem(RMR_RETRY) The message could not be sent, but the underlying transport mechanism
+ indicates that the failure is temporary. If the send operation is tried again
+ it might be successful.
+&ditem(RMR_SEND_FAILED) The send operation was not successful and the underlying transport
+ mechanism indicates a permanent (hard) failure; retrying the send is not possible.
+&ditem(RMR_ERR_BADARG) The message buffer pointer did not refer to a valid message.
+&ditem(RMR_ERR_NOHDR) The header in the message buffer was not valid or corrupted.
+&ditem(RMR_ERR_NOENDPT) The message type in the message buffer did not map to a known endpoint.
&end_dlist
&space
The following values may be assigned to &cw(errno) on failure.
&beg_dlist(.75i : ^&bold_font )
-&di(INVAL) Parameter(s) passed to the function were not valid, or the underlying message processing environment was unable to interpret the message.
+&ditem(INVAL) Parameter(s) passed to the function were not valid, or the underlying message processing environment was unable to interpret the message.
-&half_space
-&di(ENOKEY) The header information in the message buffer was invalid.
+&ditem(ENOKEY) The header information in the message buffer was invalid.
-&half_space
-&di(ENXIO) No known endpoint for the message could be found.
+&ditem(ENXIO) No known endpoint for the message could be found.
-&half_space
-&di(EMSGSIZE) The underlying transport refused to accept the message because of a size value issue (message was not attempted to be sent).
+&ditem(EMSGSIZE) The underlying transport refused to accept the message because of a size value issue (message was not attempted to be sent).
-&half_space
-&di(EFAULT) The message referenced by the message buffer is corrupt (NULL pointer or bad internal length).
+&ditem(EFAULT) The message referenced by the message buffer is corrupt (nil pointer or bad internal length).
-&half_space
-&di(EBADF) Internal RMR error; information provided to the message transport environment was not valid.
+&ditem(EBADF) Internal RMR error; information provided to the message transport environment was not valid.
-&half_space
-&di(ENOTSUP) Sending was not supported by the underlying message transport.
+&ditem(ENOTSUP) Sending was not supported by the underlying message transport.
-&half_space
-&di(EFSM) The device is not in a state that can accept the message.
+&ditem(EFSM) The device is not in a state that can accept the message.
-&half_space
-&di(EAGAIN) The device is not able to accept a message for sending. The user application should attempt to resend.
+&ditem(EAGAIN) The device is not able to accept a message for sending. The user application should attempt to resend.
-&half_space
-&di(EINTR) The operation was interrupted by delivery of a signal before the message was sent.
+&ditem(EINTR) The operation was interrupted by delivery of a signal before the message was sent.
-&half_space
-&di(ETIMEDOUT) The underlying message environment timed out during the send process.
+&ditem(ETIMEDOUT) The underlying message environment timed out during the send process.
-&half_space
-&di(ETERM) The underlying message environment is in a shutdown state.
+&ditem(ETERM) The underlying message environment is in a shutdown state.
&end_dlist
&h2(EXAMPLE)
msg_t* send_pm; // payload for send
msg_t* pm; // our message format in the received payload
- if( send_msg == NULL ) {
- send_msg = rmr_alloc_msg( mr, MAX_SIZE ); // new buffer to send
- }
+ if( send_msg == NULL ) {
+ send_msg = rmr_alloc_msg( mr, MAX_SIZE ); // new buffer to send
+ }
- // reference payload and fill in message type
+ // reference payload and fill in message type
pm = (msg_t*) send_msg->payload;
- send_msg->mtype = MT_ANSWER;
-
- msg->len = generate_data( pm ); // something that fills the payload in
- msg = rmr_send_msg( mr, send_msg );
- if( ! msg ) {
- return ERROR;
- } else {
- if( msg->state != RMR_OK ) {
- // check for eagain, and resend if needed
- // else return error
- }
- }
-
- return OK;
-
+ send_msg->mtype = MT_ANSWER;
+
+ msg->len = generate_data( pm ); // something that fills the payload in
+ msg = rmr_send_msg( mr, send_msg ); // ensure new pointer used after send
+ if( ! msg ) {
+ return ERROR;
+ } else {
+ if( msg->state != RMR_OK ) {
+ // check for RMR_ERR_RETRY, and resend if needed
+ // else return error
+ }
+ }
+ return OK;
+
&ex_end
Code Review / ric-plt / lib / rmr.git / blobdiff