Command line arguments
[Tutorials]
Collaboration diagram for Command line arguments:
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#include <unistd.h>
You must supply a series of characters in optflags, which are the legitimate options to you program. If the characher is followed by a colon (:) then that option requires an additional parameter. These parameters are returned as const char* so you must use functions like atoi() or atof() if you would like numerical results.
int parse_args(int argc, char** argv) { // set the flags const char* optflags = "h:p:i:d:u:lm:"; int ch; // use getopt to parse the flags while(-1 != (ch = getopt(argc, argv, optflags))) { switch(ch) { // case values must match long_options case 'h': // hostname gHostname = optarg; break; case 'p': // port gPort = atoi(optarg); break; case 'i': // index gIndex = atoi(optarg); break; case 'd': // debug gDebug = atoi(optarg); break; case 'u': // update rate gFrequency = atoi(optarg); break; case 'm': // datamode gDataMode = atoi(optarg); break; case 'l': // datamode gUseLaser = true; break; case '?': // help case ':': default: // unknown print_usage(argc, argv); exit (-1); } } return (0); } // end parse_args
It is also often helpfull to include a short output function that explains the option parameters to your program.
USAGE: myprogram [options]
Where [options] can be:
-h <hostname> : hostname to connect to (default: localhost)
-p <port> : port where Player will listen (default: 6665)
-i <index> : device index (default: 0)
-d <level> : debug message level (0 = none -- 9 = all)
-u <rate> : set server update rate to <rate> in Hz
-m <datamode> : set server data delivery mode
PLAYER_DATAMODE_PUSH = 1
PLAYER_DATAMODE_PULL = 2
void print_usage(int argc, char** argv) { using namespace std; cerr << "USAGE: " << *argv << " [options]" << endl << endl; cerr << "Where [options] can be:" << endl; cerr << " -h <hostname> : hostname to connect to (default: " << PlayerCc::PLAYER_HOSTNAME << ")" << endl; cerr << " -p <port> : port where Player will listen (default: " << PlayerCc::PLAYER_PORTNUM << ")" << endl; cerr << " -i <index> : device index (default: 0)" << endl; cerr << " -d <level> : debug message level (0 = none -- 9 = all)" << endl; cerr << " -u <rate> : set server update rate to <rate> in Hz" << endl; cerr << " -l : Use laser if applicable" << endl; cerr << " -m <datamode> : set server data delivery mode" << endl; cerr << " PLAYER_DATAMODE_PUSH = " << PLAYER_DATAMODE_PUSH << endl; cerr << " PLAYER_DATAMODE_PULL = " << PLAYER_DATAMODE_PULL << endl; } // end print_usage
For the complete code see examples/libplayerc++/args.h