PxMsgReceive_EvWait()

Receive a message from a mailbox while waiting for events.

APPLIES TO

8.2.0

SYNOPSIS
PxMsgEvent_t PxMsgReceive_EvWait (PxMbx_t mbxid, PxEvents_t events);
ARGUMENTS






mbxid




The mailbox handle


















events




Eventmask to wait for

















RETURN VALUES






    

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    The received message handle and/or the received events
    

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ERROR CODES















PXERR_MBX_ILLMBX




The passed mailbox handle is invalid








PXERR_MSG_NOMSG




No message available








PXERR_MSG_ILLMSG




The passed message handle is invalid








PXERR_MSG_ILLUSER




The calling task is not the user of the message








PXERR_EVENT_ZERO




The given event mask is zero









DESCRIPTION










PxMsgReceive_EvWait receives a message object from mailbox mbxid and returns the received message handle. The task becomes the user of the received message. If there is no message in the mailbox mbxid, the PxMsgReceive_EvWait waits until a message arrives or until an event from mask of events is signaled.






















IMPLEMENTATION GUIDELINES
















Before call






    

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    The parameter mbxid must be a valid mailbox object id. This id may be
    

    

      

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      the calling task’s own mailbox (V)
      

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      the result of a nameserver query (V)
      

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      part of a message sent by another task (V)
      

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    The mailbox may be checked with the macros
    

    

      

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      PxMsgIdIsValid() must be true.
      

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      PxMsgIdGet() must not be _PXIllegalObjId.
      

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      PxMsgIdError() must be PXERR_NOERROR otherwise the returned error code has to be interpreted (C).
      

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    or with a call of PxMbxCheck() (C).
    

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    The mailbox mbx must be created on the same core as the caller runs on. The creator core id can be read with the macro PxMbxCoreId and the own core id with PxGetCoreId (C).
    

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    The parameter events contains a bitmask of events awaited and should not be zero. Typically the event mask is a constant (V).
    

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After call






    

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    The returned value is a structure of type PxMsgEvent_t. The received events are stored in the events part, the message id is given in the msg part of the structure, if a message is taken from the mailbox. This id may be checked with one of the following macros:
    

    

      

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      PxMsgIdIsValid() must be true.
      

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      PxMsgIdGet() must not be _PXIllegalObjId.
      

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      PxMsgIdError() must be PXERR_NOERROR otherwise the returned error code has to be interpreted (C).
      

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Best Practice






    

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    PxMsgReceive_EvWait may block, if no message is available at the mailbox  and no instance (task or handler) sends an event. If blocking calls are prohibited, PxMsgReceive_NoWait() should be used instead or the call should be monitored by the PXROS-HR PxTo mechanism.
    

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SEE ALSO











USAGE








#include "pxdef.h"

#define MY_EVENT_MASK 0x1l

PxMsgEvent_t msgEvHnd = PxMsgReceive_EvWait(mbxid, MY_EVENT_MASK);

if (PxMsgIdIsValid (msgEvHnd.msg)) {
    /// Request successful - handle message
}
else if (msgEvHnd.events & MY_EVENT_MASK) {
    // Request not successful - interrupted by event
}
else
{
    // Request not successful - check the msgEvHnd.msg.error
}