Sends an N-ACTION-REQ message to a peer member of a connection. This function is available in the PACS Imaging Toolkit.


#include "ltdic.h"

L_INT LDicomNet::SendNActionRequest(nPresentationID, nMessageID, pszClass, pszInstance, nAction, pDS)


L_UCHAR nPresentationID

Presentation ID. The presentation ID provides information about both the class type of the data and the transfer syntax to use when transferring the data.

L_UINT16 nMessageID

Message ID. Each message sent by a member of a connection should have a unique ID. Since a member of a connection may send several messages, this ID allows that member to identify when a specific request has been completed.

L_TCHAR * pszClass

Class affected by the request. This will be an SOP Class or an SOP MetaClass.

L_TCHAR * pszInstance

The instance of the class. A server may, for example, have three instances of the Nuclear Medicine Class. This value identifies the data with a specific instance.

L_UINT16 nAction

An application specific action to be performed on the specified data set.

LDicomDS *pDS

The data set on which the specified action is to be performed.


Value Meaning
>0 An error occurred. Refer to Return Codes.


Calling this function generates a call to LDicomNet::OnReceiveNActionRequest on the SCP. The SCP should respond by calling LDicomNet::SendNActionResponse which will generate a call to LDicomNet::OnReceiveNActionResponse.

The action specified may be the addition of a new patient, the deletion of a patient, the addition of a new study, a print job, etc. The nAction value, which designates the action to perform is determined by the server. To find out the values used, you must contact the organization that created the server. When creating a server, the values and their corresponding meanings are determined by those creating the server.

Required DLLs and Libraries


Win32, x64

See Also




This sample sends an N-Action Request to the server
In this example:

  1. LMyDicomNet is a class derived from LDicomNet
  2. LMyDicomNet has the following member variables:
    identifies the LMyDicomNet object as a server or a client
    m_nDataCommand: can be (COMMAND_C_MOVE,COMMAND_C_GET)
    set so the server knows how a C-Store Response was generated
  3. m_pDicomNet points to a valid LMyDicomNet object
    LMyDicomNet *m_pDicomNet

  4. A connection exists between client and server

  5. An association exists between the client and server
    L_INT LDicomNet__SendNActionRequestExample(LMyDicomNet *m_pDicomNet) 
       L_INT nRet; 
       CString strMsg = TEXT("N-Action\n"); 
       //Choose a supported Action ID 
       L_UINT16 nAction = 1; 
       //Choose an SOP Class to find 
       CString strClassUID = UID_BASIC_FILM_BOX_CLASS; 
       //Choose an SOP Instance to modify 
       CString strInstanceUID = TEXT(""); 
       //...Create a data set that encodes the Action Arguments (based on value of nAction) 
       //...For this example, add a tag to the Data set so that it is non-empty 
       LDicomDS DicomDS; 
       DicomDS.InitDS(CLASS_UNKNOWN, 0); 
       //...Add the action arugments 
       pDICOMTAG pDicomTag = LDicomTag::Find(TAG_IMAGE_TYPE); 
       pDICOMELEMENT pElement = DicomDS.InsertElement(  
                               NULL,                      //pDICOMELEMENT pNeighbor 
                               FALSE,                     //L_BOOL bChild 
                               TAG_IMAGE_TYPE,            //L_UINT32 nTag 
                               pDicomTag->nVR,            //L_UINT16 nVR       
                               FALSE,                     //L_BOOL bSequence, 
                               0                          //L_UINT32 nIndex 
       //Get the associate object 
       LDicomAssociate *pDicomAssociate = m_pDicomNet->GetAssociate(); 
       //Is class supported in the assocation? 
       L_UCHAR nPresentationID = pDicomAssociate->FindAbstract((L_TCHAR *)(LPCTSTR)strClassUID); 
       //nPresentationID must be odd--0 indicates failure 
       if (nPresentationID==0) 
          CString strTmp; 
          strTmp.Format(TEXT("Abstract Syntax[%s] Not Included in the Association"), strClassUID); 
          strMsg = strMsg + strTmp; 
       else //success 
          L_UINT16 uUniqueID = 99; 
          nRet =m_pDicomNet->SendNActionRequest( nPresentationID,  
                                           (L_TCHAR *)(LPCTSTR)strClassUID,  
                                           (L_TCHAR *)(LPCTSTR)strInstanceUID,  
          if(nRet > 0) 
             return nRet; 
       return DICOM_SUCCESS; 
Help Version 22.0.2022.12.7
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LEADTOOLS DICOM C++ Class Library Help

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.