kern/user/progDE.c

#include <common.h>

/**
** User function main #2:  write
**
** Prints its ID, then loops N times delaying and printing, then returns
** without calling exit(). Verifies the return byte count from each call
** to write().
**
** Invoked as:  main2  x  n
**	 where x is the ID character
**		   n is the iteration count
*/

USERMAIN(main)
{
	int n;
	int count = 30; // default iteration count
	char ch = '2'; // 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, "main2: 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
	n = swritech(ch);
	if (n != 1) {
		sprint(buf, "== %c, write #1 returned %d\n", ch, n);
		cwrites(buf);
	}

	// iterate and print the required number of other characters
	for (int i = 0; i < count; ++i) {
		DELAY(STD);
		n = swritech(ch);
		if (n != 1) {
			sprint(buf, "== %c, write #2 returned %d\n", ch, n);
			cwrites(buf);
		}
	}

	// all done!
	return (0);
}