//open the audio file
infile = sf_open(name_of_file, SFM_READ, &sfinfo);

//get information of audio file
cout << "Samplerate = " << sfinfo.samplerate << endl;
cout << "Channels = " << sfinfo.channels << endl;

//...
//read until the end file
while(sf_seek(infile, 0, SEEK_CUR) <  sfinfo.frames)
{
    //Reading N samples
    sf_readf_double(infile, samples, N);
            //...
    }