Currently I am analysing the constructor below:
Foam::argList::argList
372 (
373 int& argc, // argc of main
374 char**& argv, // argv of main
375 bool checkArgs,
376 bool checkOpts
377 )
378 : //Initializing
379 args_(argc), //stringList args_ with size argc
380 options_(argc) //HashTable<string> options_ with size argc
381 {
382 // Check if this run is a parallel run by searching for any parallel option
383 // If found call runPar which might filter argv
384 for (int argI = 0; argI < argc; ++argI)
385 {
386 if (argv[argI][0] == '-') //argv is array of pointers //HERE
387 { //inline const Foam::string& Foam::argList::operator[]
//(const label index) const
//{
//return args_[index];
//}
388 const char *optionName = &argv[argI][1]; //Adressenzuordnung
389
390 if (validParOptions.found(optionName))
391 {
392 parRunControl_.runPar(argc, argv);
393 break;
394 }
395 }
396 }
I have a question about line 386:
argv should be an array of pointers given as parameter to main(...). With argv[argI] I access the element argI of argv and with [0] the overloaded operator method [] ist called. I really don't get what exactly is happening here, perhaps I am missinterpreting something?
As you mentioned, argv is a char **. argv[x][y] means the y'th element of the x'th pointer. To be more specific, the point of that line is to check if the command line parameter starts with a dash. It has nothing to do with operator overloading, it is a simple acces of an array of pointers.
Let's see an example:
./a.out -bar -foo baz 32 -3
The condition checks for all command line parameters if they begin with a dash. So, it is true for -bar, -foo, -3 but not for baz and 32.