98 lines
2.9 KiB
HTML
98 lines
2.9 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML>
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<HEAD>
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<TITLE>#define CmdLineArgs</TITLE>
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<META NAME="GENERATOR" CONTENT="DOC++ 3.4.8">
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</HEAD>
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<BODY BGCOLOR="#ffffff">
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<H2>#define <A HREF="#DOC.DOCU">CmdLineArgs</A></H2></H2><A NAME="DOC.DOCU"></A>
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<BLOCKQUOTE>
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<P>
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A collection of utilities for processing command line arguments.
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<P>An osgGA::CmdLineArgs::Processor class is provided, which implements a chain
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of responsibilty for handline command line arguments. Each item in the chain
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is a subclass of the abstract osgGA::CmdLineArgs::ArgHandler. A number
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of ArgHandlers are provided, though the user if free to implement their
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own subclasses for specific needs (e.g. to validate an argument which
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takes an integer which must be in a specific range).
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<P>Let's look at an example...
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<P><h2>Example</h2>
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<P>\code
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<P>#include <osgGA/CmdLineArgs>
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<P>int main(int argc, char* argv[])
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{
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using namespace osg;
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using namespace osgGA::CmdLineArgs;
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<P>// Create some handlers
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ref_ptr<BoolHandler> helpSwitch(new BoolHandler("[-h]","\t\tPrint this help and exit","-h"));
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ref_ptr<BoolHandler> verboseSwitch(new BoolHandler("[-v]","\t\tActivate verbose output","-v"));
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ref_ptr<SwitchStringHandler> configFile(
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new SwitchStringHandler("[-config <configfile>",
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"\t\tSpecify a config file to load"), "-config");
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<P>Processor clp;
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clp.push_back(helpSwitch.get());
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clp.push_back(verboseSwitch.get());
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clp.push_back(configFile.get());
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<P>try{
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clp.process(argc,argv);
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}
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catch(ArgHandlerX& e){
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cerr<<e.what()<<endl;
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clp.printUsage(cerr);
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exit(1);
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}
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catch(...){
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cerr<<"Unknown exception caught while processing command line arguments."<<endl;
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clp.printUsage(cerr);
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exit(1);
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}
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<P>if(helpSwitch->wasSpecified()){
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clp.printHelp(cerr);
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exit(0);
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}
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<P>if(verboseSwitch->wasSpecified()){
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// Activate verbosity...
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}
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<P>if(configFile->wasSpecified()){
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loadConfigFile(configFile->getString());
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}
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<P>}
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<P>\endcode
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<P>The processor takes each argument on the command line in turn, and passes it
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to the ArgHandler chain. Each ArgHandler is given the opportunity to handle
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an argument and - if it requires - any subsequent arguments until the
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end of the argument list (it can do this by incrementing the ArgIterator
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passed to it. If an ArgHandler handles an argument (e.g. it's looking for
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and recognises the argument '-h'), it returns true and further processing of
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the argument stops. If an argument is not handled it is passed to the next
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handler in the chain, and so on, until it is either handled, or it drops off
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the end of the chain.
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<P>A number of pre-written ArgHandlers are supplied. User's may use these
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directly, may write their own, or may extend a pre-written ArgHandler to
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customise it for their specific needs.
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</BLOCKQUOTE>
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<DL><DT><DD></DL><P><P><I><A HREF="index.html">Alphabetic index</A></I> <I><A HREF="HIER.html">Hierarchy of classes</A></I></P><HR>
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<BR>
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This page was generated with the help of <A HREF="http://docpp.sourceforge.net">DOC++</A>.
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</BODY>
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</HTML>
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