29 #define check(x) do if (!(x)) { \  macro
37   check(argc >= 1 + 2 + 1); /* Need at least 2 input files + 1 output file. */  in main()
38   check(sox_init() == SOX_SUCCESS);  in main()
54     check(input = sox_open_read(argv[i], NULL, NULL, NULL));  in main()
65       check(output = sox_open_write(argv[argc - 1],  in main()
75       check(input->signal.channels == signal.channels);  in main()
76       check(input->signal.rate == signal.rate);  in main()
81       check(sox_write(output, samples, number_read) == number_read);  in main()
83     check(sox_close(input) == SOX_SUCCESS); /* Finished with this input file.*/  in main()
86   check(sox_close(output) == SOX_SUCCESS); /* Finished with the output file. */  in main()
88   check(sox_quit() == SOX_SUCCESS);  in main()