332 static const char *progname;    /* program name for error messages */  variable
342   fprintf(stderr, "Usage: %s [switches] ", progname);  in usage()
408   progname = argv[0];  in main()
409   if (progname == NULL || progname[0] == 0)  in main()
410     progname = "wrjpgcom";      /* in case C library doesn't provide it */  in main()
423         fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);  in main()
481       fprintf(stderr, "%s: can't open %s\n", progname, argv[argn]);  in main()
491       fprintf(stderr, "%s: can't open stdin\n", progname);  in main()
503     fprintf(stderr, "%s: must name one input and one output file\n", progname);  in main()
507     fprintf(stderr, "%s: can't open %s\n", progname, argv[argn + 1]);  in main()
513     fprintf(stderr, "%s: only one input file\n", progname);  in main()
522     fprintf(stderr, "%s: can't open stdout\n", progname);  in main()