#include /** ** User function J: exit, fork, exec, write ** ** Reports, tries to spawn lots of children, then exits ** ** Invoked as: userJ x [ n ] ** where x is the ID character ** n is the number of children to spawn (defaults to 2 * N_PROCS) */ USERMAIN(main) { int count = 2 * N_PROCS; // number of children to spawn char ch = 'j'; // default character to print char buf[128]; // process the command-line arguments switch (argc) { case 3: count = str2int(argv[2], 10); // FALL THROUGH case 2: ch = argv[1][0]; break; default: sprint(buf, "userJ: argc %d, args: ", argc); cwrites(buf); for (int i = 0; i <= argc; ++i) { sprint(buf, " %s", argv[argc] ? argv[argc] : "(null)"); cwrites(buf); } cwrites("\n"); } // announce our presence write(CHAN_SIO, &ch, 1); // set up the command-line arguments char *argsy[] = { "userY", "Y", "10", NULL }; for (int i = 0; i < count; ++i) { int whom = spawn(ProgY, argsy); if (whom < 0) { write(CHAN_SIO, "!j!", 3); } else { write(CHAN_SIO, &ch, 1); } } exit(0); return (42); // shut the compiler up! }