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#include <common.h>
/**
** User function H: exit, fork, exec, sleep, write
**
** Prints its ID, then spawns 'n' children; exits before they terminate.
**
** Invoked as: userH x n
** where x is the ID character
** n is the number of children to spawn
*/
USERMAIN(main)
{
int32_t ret = 0; // return value
int count = 5; // child count
char ch = 'h'; // default character to print
char buf[128];
int whom;
// process the argument(s)
switch (argc) {
case 3:
count = str2int(argv[2], 10);
// FALL THROUGH
case 2:
ch = argv[1][0];
break;
default:
sprint(buf, "userH: 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
swritech(ch);
// we spawn user Z and then exit before it can terminate
// userZ 'Z' 10
char *argsz[] = { "userZ", "Z", "10", NULL };
for (int i = 0; i < count; ++i) {
// spawn a child
whom = spawn(ProgZ, argsz);
// our exit status is the number of failed spawn() calls
if (whom < 0) {
sprint(buf, "!! %c spawn() failed, returned %d\n", ch, whom);
cwrites(buf);
ret += 1;
}
}
// yield the CPU so that our child(ren) can run
sleep(0);
// announce our departure
swritech(ch);
exit(ret);
return (42); // shut the compiler up!
}
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