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CONTROL Functions
Functions X
xmlFirstChild()
Returns an internal ID to the first child node in the DOM tree.

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Business Logic / Control
Endless possibilities in data processing for your projects.
- Introduction to CTRL
  An introduction to the product's own programming language Control(CTRL).
- Control Classes
  The overview of classes available in Control.
- Types of Control Functions
  An overview of the types of functions distinguished within Control.
- Control graphics
- CONTROL Functions
  - Funtions A
  - Funtions B
  - Funtions C
  - Funtions D
  - Functions E
  - Functions F
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  - Functions V
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  - Functions X
    - xmlAppendChild()
      Adds a new child node into the DOM tree as child of given node. Optionally the node's value can be set.
    - xmlChildNodes()
      Writes all child nodes of the given node into the nodes' reference parameter.
    - xmlCloseDocument()
      Closes the created XML document and destroys the occupied memory. After this call, the document ID is no longer valid.
    - xmlDocumentFromFile()
      Opens a file and reads the complete content building the DOM structure in memory.
    - xmlDocumentFromString()
      Reads the complete content from a string and builds the DOM structure in memory.
    - xmlDocumentToFile()
      Stores the internal DOM tree in an arbitrary XML file.
    - xmlDocumentToString()
      Returns the internal DOM tree as a string result.
    - xmlElementAttributes()
      Returns all node attributes as a mapping.
    - xmlFirstChild()
      Returns an internal ID to the first child node in the DOM tree.
    - xmlGetElementAttribute()
      Reads the value of the given attribute into the value reference parameter of the node.
    - xmlIsSameNode()
      Checks whether two node IDs are pointing to the same internal node within the DOM tree.
    - xmlNamedChild()
      This function allows you to easily find a child node in an xml document.
    - xmlNewDocument()
      Starts the creation of a new document in memory and returns the document ID.
    - xmlNextSibling()
      Returns an internal ID for the next sibling of the given node.
    - xmlNodeName()
      Returns the name of a node.
    - xmlNodePosition()
      The function returns the position of a node inside of an XML document.
    - xmlNodeType()
      Returns the type of the given node.
    - xmlNodeValue()
      Returns the value of the given node.
    - xmlParentNode()
      Returns the internal ID for the parent node of the given node.
    - xmlRemoveElementAttribute()
      Removes the given attribute from its node.
    - xmlRemoveNode()
      Removes the given node from its parent node.
    - xmlrpcCall()
      Calls the function "function" on the server with the arguments of the parameter "args". If "result" is specified, the function waits for the answer from the server and saves the answer in "result". This corresponds to the call result = function(args[1], ...);
    - xmlrpcClient
      Starts an XmlRpc client. The XmlRpc client is a Ctrl module that handles the calls in the background.
    - xmlrpcCloseServer()
      Closes the connection to the server.
    - xmlrpcConnectToServer()
      Establishes a connection to an XmlRpc server on host "host" and port "port". If "secure" is TRUE, a https connection is built. Under Windows the OpenSSL installation is required. The connection is valid only as long as it is open. This means if the connection is broken, the requests for the server will fail. Using the parameter "id", the server can be identified in the following calls.
    - xmlrpcDecodeRequest()
      Decodes the request and extracts the function name and arguments of it.
    - xmlrpcDecodeValue()
      Re-converts an XmlRpc-coded string to a variable.
    - xmlrpcEncodeResponse()
      Encodes the result in an XmlRpc message.
    - xmlrpcEncodeValue()
      Converts a "value" variable to an XmlRpc-coded string.
    - xmlrpcHandler()
      CtrlXmlRpc is a CTRL extension including XML-RPC functions. XML-RPC is a protocol for web services, similar to SOAP but much simpler.
    - xmlrpcSetGzipLimit()
      Defines from which size the contents of a request are compressed (gzip).
    - xmlSetElementAttribute()
      Sets the attribute of a node to given value.
    - xmlSetNodeValue()
      Sets the node's value to the given value.
  - Functions Y
  - Functions Z
- CtrlExtension
  The CtrlExtension allows the addition of custom C++ code.
- CTRL Debugger
  You can use the CTRL debugger to debug the Control programming language. The debugger can be used via its own panel, which also enables the monitoring and setting of variable values during the execution of a script.
- SQL in CONTROL
  The database functions enable you to quickly carry out value queries on data points and elements.
- API Manager
  The WinCC OA API (Application Programming Interface) offers a number of functions adding special Managers to this process control system.
- NextGen Archiver Backend-API
  This chapter describes the NextGen Archiver Backend API
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The process connection to the actual machines/sensors.
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Data exchange, APIs and web technologies
User Management
All about authorization, authentication and login-customization.
Availability
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Reporting
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Useful tools and enhancements for special demands.
Reference Tables
Detailed and extensive content for special project adaptation.
Videos & Tutorials
Explore the capabilities of WinCC OA with our carefully selected collection of video tutorials and guides.
WinCC OA Documentation
Basic information about terms and functions within the documentation.
Disclaimer
A brief clarification of liability exclusions or legal notices.

xmlFirstChild()

Returns an internal ID to the first child node in the DOM tree.

Synopsis

int xmlFirstChild(unsigned doc[, unsigned node]);

Parameters


Parameter	Description
doc	The document ID returned by e.g. xmlNewDocument().
node	Optional parameter. The node whose child node ID will be returned. If the node argument is not given, it returns the root node of the tree.

Return value

If the node argument is not given, it returns the root node of the tree.

It returns -1 if this node does not exist.

Description

Returns an internal ID to the first child node in the DOM tree.

Example

This example eads the d:/XmlTest0.xml file and creates a document. The content of the document is printed using printNodes. The function xmlElementAttributes returns all node attributes as a mapping.

#uses "CtrlXml"
global uint docNum;
global string err;
global int errLine, errColumn;
main()
{
  uint node;
  DebugN(docNum = xmlDocumentFromFile("d:/XmlTest0.xml", err,
  errLine,
  errColumn));
  DebugN("error:", err, errLine, errColumn);
  printNodes(node = xmlFirstChild(docNum));
  xmlSetElementAttribute(docNum, node, "test_attribute", "some
  fancy
  value !!");
}
void printNodes(int node)
{
  if ( node != -1 )
  {
    if ( xmlNodeType(docNum, node) == XML_TEXT_NODE )
    DebugN("value:", xmlNodeValue(docNum, node));
    if ( xmlNodeType(docNum, node) == XML_ELEMENT_NODE )
    DebugN(xmlNodeName(docNum, node), xmlElementAttributes(docNum,
    node) );
    printNodes(xmlFirstChild(docNum, node));
    printNodes(xmlNextSibling(docNum, node));
    DebugN(xmlDocumentFromFile(docNum, "d:/XmlTest0.xml",err,
    errLine,
    errColumn));
  }
}

Assignment

XML Control Extension

Availability

CTRL. In every script where the "CtrlXml" extension (#uses "CtrlXml") is used.