Add route table guide and formatting tweaks

[ric-plt/lib/rmr.git] / docs / rmr_send_msg.3.rst

diff --git a/docs/rmr_send_msg.3.rst b/docs/rmr_send_msg.3.rst
index 5f30eeb..06487be 100644 (file)
--- a/docs/rmr_send_msg.3.rst
+++ b/docs/rmr_send_msg.3.rst
@@ -1,73 +1,68 @@
- 
- 

 .. This work is licensed under a Creative Commons Attribution 4.0 International License. 
 .. SPDX-License-Identifier: CC-BY-4.0 
 .. CAUTION: this document is generated from source in doc/src/rtd. 
 .. To make changes edit the source and recompile the document. 
 .. Do NOT make changes directly to .rst or .md files. 
  
 .. This work is licensed under a Creative Commons Attribution 4.0 International License. 
 .. SPDX-License-Identifier: CC-BY-4.0 
 .. CAUTION: this document is generated from source in doc/src/rtd. 
 .. To make changes edit the source and recompile the document. 
 .. Do NOT make changes directly to .rst or .md files. 
  

- 

 ============================================================================================ 
 Man Page: rmr_send_msg 
 ============================================================================================ 
  
 ============================================================================================ 
 Man Page: rmr_send_msg 
 ============================================================================================ 
  

-RMR Library Functions 
-============================================================================================ 
- 
- 
-NAME 
--------------------------------------------------------------------------------------------- 

  
  

+
+
+RMR LIBRARY FUNCTIONS
+=====================
+
+
+
+NAME
+----
+

 rmr_send_msg 
 rmr_send_msg 

- 
-SYNOPSIS 
--------------------------------------------------------------------------------------------- 
- 
+
+
+SYNOPSIS
+--------
+

  
 :: 
  
 :: 

-  
+ 

  #include <rmr/rmr.h>
  #include <rmr/rmr.h>

+  

  rmr_mbuf_t* rmr_send_msg( void* vctx, rmr_mbuf_t* msg );
  
  rmr_mbuf_t* rmr_send_msg( void* vctx, rmr_mbuf_t* msg );
  

- 
- 
-DESCRIPTION 
--------------------------------------------------------------------------------------------- 
- 
-The 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. 
-This may actually result in the sending of the message to 
-multiple destinations which could degrade expected overall 
-performance of the user application. (Limiting excessive 
-sending of messages is the responsibility of the 
+
+
+DESCRIPTION
+-----------
+
+The ``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. This may actually result in the sending of the 
+message to multiple destinations 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 responsibility of the 
 library.) 
 application(s) responsible for building the routing table 
 used by the RMR library, and not the responsibility of the 
 library.) 

- 
-Retries 
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
- 
+
+
+Retries
+-------
+

 The send operations in RMR will retry *soft* send failures 
 until one of three conditions occurs: 
  
  
 The send operations in RMR will retry *soft* send failures 
 until one of three conditions occurs: 
  
  

- 
-1. 
-   
-  The message is sent without error 
-   
- 
-2. 
-   
-  The underlying transport reports a *hard* failure 
-   
- 
-3. 
-   
-  The maximum number of retry loops has been attempted 
+ &item The message is sent without error 
+  
+ &item The underlying transport reports a *hard* failure 
+  
+ &item The maximum number of retry loops has been attempted 

  
  
 A retry loop consists of approximately 1000 send attempts 
  
  
 A retry loop consists of approximately 1000 send attempts 


@@ -78,10 +73,11 @@ application. This value can be set at any point after RMR
 initialisation using the *rmr_set_stimeout()* function 
 allowing the user application to completely disable retires 
 (set to 0), or to increase the number of retry loops. 
 initialisation using the *rmr_set_stimeout()* function 
 allowing the user application to completely disable retires 
 (set to 0), or to increase the number of retry loops. 

- 
-Transport Level Blocking 
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 
- 
+
+
+Transport Level Blocking
+------------------------
+

 The underlying transport mechanism used to send messages is 
 configured in *non-blocking* mode. This means that if a 
 message cannot be sent immediately the transport mechanism 
 The underlying transport mechanism used to send messages is 
 configured in *non-blocking* mode. This means that if a 
 message cannot be sent immediately the transport mechanism 


@@ -100,14 +96,15 @@ RMR can do to avoid or mitigate these other than by allowing
 RMR to retry the send operation, and even then it is possible 
 (e.g., during connection reattempts), that a single retry 
 loop is not enough to guarantee a successful send. 
 RMR to retry the send operation, and even then it is possible 
 (e.g., during connection reattempts), that a single retry 
 loop is not enough to guarantee a successful send. 

- 
-RETURN VALUE 
--------------------------------------------------------------------------------------------- 
- 
+
+
+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 
 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 will be RMR_OK when the send was successful. 
+state and will be ``RMR_OK`` when the send was successful. 

  
 When the message cannot be successfully sent this function 
 will return the unsent (original) message buffer with the 
  
 When the message cannot be successfully sent this function 
 will return the unsent (original) message buffer with the 


@@ -116,7 +113,7 @@ state set to indicate the reason for failure. The value of
 reason if it is known. 
  
 In the event of extreme failure, a nil pointer is returned. 
 reason if it is known. 
  
 In the event of extreme failure, a nil pointer is returned. 

-In this case the value of errno might be of some use, for 
+In this case the value of ``errno`` might be of some use, for 

 documentation, but there will be little that the user 
 application can do other than to move on. 
  
 documentation, but there will be little that the user 
 application can do other than to move on. 
  


@@ -124,141 +121,142 @@ application can do other than to move on.
 message returned by the send function does **not** reference 
 the same memory structure. Thus is important for the user 
 programme to capture the new pointer for future use or to be 
 message returned by the send function does **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 rmr_free(). If you are experiencing either double 
-free errors or segment faults in either rmr_free() or 
-rmr_send_msg(), ensure that the return value from this 
-function is being captured and used. 
- 
-ERRORS 
--------------------------------------------------------------------------------------------- 
- 
+passed to ``rmr_free().`` If you are experiencing either 
+double free errors or segment faults in either 
+``rmr_free()`` or ``rmr_send_msg(),`` ensure that the return 
+value from this function is being captured and used. 
+
+
+ERRORS
+------
+

 The following values may be passed back in the *state* field 
 of the returned message buffer. 
  
  
 The following values may be passed back in the *state* field 
 of the returned message buffer. 
  
  

- 
-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. 
- 
-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. 
- 
-RMR_ERR_BADARG 
-   
-  The message buffer pointer did not refer to a valid 
-  message. 
- 
-RMR_ERR_NOHDR 
-   
-  The header in the message buffer was not valid or 
-  corrupted. 
- 
-RMR_ERR_NOENDPT 
-   
-  The message type in the message buffer did not map to a 
-  known endpoint. 
- 
- 
-The following values may be assigned to errno on failure. 
- 
- 
-INVAL 
-   
-  Parameter(s) passed to the function were not valid, or the 
-  underlying message processing environment was unable to 
-  interpret the message. 
-   
- 
-ENOKEY 
-   
-  The header information in the message buffer was invalid. 
-   
- 
-ENXIO 
-   
-  No known endpoint for the message could be found. 
-   
- 
-EMSGSIZE 
-   
-  The underlying transport refused to accept the message 
-  because of a size value issue (message was not attempted 
-  to be sent). 
-   
- 
-EFAULT 
-   
-  The message referenced by the message buffer is corrupt 
-  (nil pointer or bad internal length). 
-   
- 
-EBADF 
-   
-  Internal RMR error; information provided to the message 
-  transport environment was not valid. 
-   
- 
-ENOTSUP 
-   
-  Sending was not supported by the underlying message 
-  transport. 
-   
- 
-EFSM 
-   
-  The device is not in a state that can accept the message. 
-   
- 
-EAGAIN 
-   
-  The device is not able to accept a message for sending. 
-  The user application should attempt to resend. 
-   
- 
-EINTR 
-   
-  The operation was interrupted by delivery of a signal 
-  before the message was sent. 
-   
- 
-ETIMEDOUT 
-   
-  The underlying message environment timed out during the 
-  send process. 
-   
- 
-ETERM 
-   
-  The underlying message environment is in a shutdown state. 
- 
- 
-EXAMPLE 
--------------------------------------------------------------------------------------------- 
- 
-The following is a simple example of how the rmr_send_msg 
-function is called. In this example, the send message buffer 
-is saved between calls and reused eliminating alloc/free 
-cycles. 
+   .. list-table:: 
+     :widths: auto 
+     :header-rows: 0 
+     :class: borderless 
+      
+     * - **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. 
+      
+     * - **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. 
+      
+     * - **RMR_ERR_BADARG** 
+       - 
+         The message buffer pointer did not refer to a valid message. 
+      
+     * - **RMR_ERR_NOHDR** 
+       - 
+         The header in the message buffer was not valid or corrupted. 
+      
+     * - **RMR_ERR_NOENDPT** 
+       - 
+         The message type in the message buffer did not map to a known 
+         endpoint. 
+          
+ 
+ 
+The following values may be assigned to ``errno`` on failure. 
+ 
+   .. list-table:: 
+     :widths: auto 
+     :header-rows: 0 
+     :class: borderless 
+      
+     * - **INVAL** 
+       - 
+         Parameter(s) passed to the function were not valid, or the 
+         underlying message processing environment was unable to 
+         interpret the message. 
+      
+     * - **ENOKEY** 
+       - 
+         The header information in the message buffer was invalid. 
+      
+     * - **ENXIO** 
+       - 
+         No known endpoint for the message could be found. 
+      
+     * - **EMSGSIZE** 
+       - 
+         The underlying transport refused to accept the message 
+         because of a size value issue (message was not attempted to 
+         be sent). 
+      
+     * - **EFAULT** 
+       - 
+         The message referenced by the message buffer is corrupt (nil 
+         pointer or bad internal length). 
+      
+     * - **EBADF** 
+       - 
+         Internal RMR error; information provided to the message 
+         transport environment was not valid. 
+      
+     * - **ENOTSUP** 
+       - 
+         Sending was not supported by the underlying message 
+         transport. 
+      
+     * - **EFSM** 
+       - 
+         The device is not in a state that can accept the message. 
+      
+     * - **EAGAIN** 
+       - 
+         The device is not able to accept a message for sending. The 
+         user application should attempt to resend. 
+      
+     * - **EINTR** 
+       - 
+         The operation was interrupted by delivery of a signal before 
+         the message was sent. 
+      
+     * - **ETIMEDOUT** 
+       - 
+         The underlying message environment timed out during the send 
+         process. 
+      
+     * - **ETERM** 
+       - 
+         The underlying message environment is in a shutdown state. 
+          
+ 
+
+
+EXAMPLE
+-------
+
+The following is a simple example of how the 
+``rmr_send_msg`` function is called. In this example, the 
+send message buffer is saved between calls and reused 
+eliminating alloc/free cycles. 

  
  
 :: 
  
  
 :: 

-  
+ 

      static rmr_mbuf_t*  send_msg = NULL;        // message to send; reused on each call
      msg_t*  send_pm;                            // payload for send
      msg_t*  pm;                                 // our message format in the received payload
      static rmr_mbuf_t*  send_msg = NULL;        // message to send; reused on each call
      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
      pm = (msg_t*) send_msg->payload;
      send_msg->mtype = MT_ANSWER;
      // 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 );   // ensure new pointer used after send
      if( ! msg ) {
      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 ) {


@@ -270,12 +268,13 @@ cycles.
          }
      }
      return OK;
          }
      }
      return OK;

+  

  
  

- 
- 
-SEE ALSO 
--------------------------------------------------------------------------------------------- 
- 
+
+
+SEE ALSO
+--------
+

 rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3), 
 rmr_payload_size(3), rmr_rcv_msg(3), rmr_rcv_specific(3), 
 rmr_rts_msg(3), rmr_ready(3), rmr_mk_ring(3), 
 rmr_alloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3), 
 rmr_payload_size(3), rmr_rcv_msg(3), rmr_rcv_specific(3), 
 rmr_rts_msg(3), rmr_ready(3), rmr_mk_ring(3),