1 files changed, 57 insertions, 0 deletions
diff --git a/user/progZ.c b/user/progZ.c
new file mode 100644
index 0000000..cc394c4
--- /dev/null
+++ b/user/progZ.c
@@ -0,0 +1,57 @@
+#include <common.h>
+
+/**
+** 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!
+}