RtAudio example using API names

example.cc

#include <RtAudio.h>
#include <getopt.h>
#include <iostream>

static void print_compiled_apis()
{
    std::vector<RtAudio::Api> available;
    RtAudio::getCompiledApi(available);
    for (RtAudio::Api api : available)
        std::cout << " * " << RtAudio::getCompiledApiName(api) << "\n";
}

int main(int argc, char *argv[])
{
    RtAudio::Api api = RtAudio::UNSPECIFIED;
    const char *desired_api = nullptr;

    std::cout << "usage: example [-d api] [-h]\n\n";

    int arg;
    while ((arg = getopt(argc, argv, "d:h")) != -1) {
        if (arg == 'd') {
            desired_api = optarg;
            api = RtAudio::getCompiledApiByName(desired_api);
        }
        else if (arg == 'h') {
            print_compiled_apis();
            return 0;
        }
    }

    if (desired_api && api == RtAudio::UNSPECIFIED) {
        std::cout << "API unavailable '" << desired_api << "'.\n";
        print_compiled_apis();
        return 1;
    }

    RtAudio *audiosys = new RtAudio(api);
    api = audiosys->getCurrentApi();
    std::cout << "Audio is open with API '" << RtAudio::getCompiledApiName(api) << "'.\n";
    /* ... */
    return 0;
}