53   FILE *fp;  in main()  local
57   fp = fropen(&cookie_var, f_read);  in main()
58   assert(fp);  in main()
60   assert(fileno(fp) == -1);  in main()
61   assert(fgets(buf, sizeof(buf), fp));  in main()
63   assert(!fclose(fp));  in main()
66   fp = fwopen(&cookie_var, f_write);  in main()
67   assert(fp);  in main()
68   assert(fileno(fp) == -1);  in main()
69   assert(fputs("test", fp) >= 0);  in main()
70   assert(!fclose(fp));  in main()
73   fp = funopen(&cookie_var, f_read, f_write, NULL, f_close);  in main()
74   assert(fp);  in main()
75   assert(fileno(fp) == -1);  in main()
76   assert(fgets(buf, sizeof(buf), fp));  in main()
78   assert(fputs("test", fp) >= 0);  in main()
79   assert(!fclose(fp));  in main()
82   fp = funopen(&cookie_var, f_read, NULL, f_seek, NULL);  in main()
83   assert(fp);  in main()
84   assert(fileno(fp) == -1);  in main()
85   assert(fseek(fp, 100, SEEK_SET) == 0);  in main()
86   assert(fgets(buf, sizeof(buf), fp));  in main()
88   assert(!fclose(fp));  in main()