--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/calypso/targetfd.c	Sun Mar 14 05:07:34 2021 +0000
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int target_fd;
+
+parse_target_fd_opt(argc, argv)
+	char **argv;
+{
+	extern char *optarg;
+	int c;
+
+	while ((c = getopt(argc, argv, "C:")) != EOF) {
+		switch (c) {
+		case 'C':
+			target_fd = atoi(optarg);
+			continue;
+		case '?':
+		default:
+			/* error msg already printed */
+			exit(1);
+		}
+	}
+	if (!target_fd) {
+		fprintf(stderr, "error: target fd must be given with -C\n");
+		exit(1);
+	}
+	return(0);
+}