#include /** ** User function Z: exit, sleep, write, getpid ** ** Prints its ID, then records PID and PPID, loops printing its ID, ** and finally re-gets PPID for comparison. Yields after every second ** ID print in the loop. ** ** This code is used as a handy "spawn me" test routine; it is spawned ** by several of the standard test processes. ** ** Invoked as: userZ x [ n ] ** where x is the ID character ** n is the iteration count (defaults to 10) */ USERMAIN(main) { int count = 10; // default iteration count char ch = 'z'; // 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, "?: 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 int pid = getpid(); sprint(buf, " %c[%d]", ch, pid); swrites(buf); // iterate for a while; occasionally yield the CPU for (int i = 0; i < count; ++i) { sprint(buf, " %c[%d]", ch, i); swrites(buf); DELAY(STD); if (i & 1) { sleep(0); } } exit(0); return (42); // shut the compiler up! }