2006-04-25 Roland McGrath <roland@redhat.com>

* strace.c (main): Fail when -c is given with -ff.
	* strace.1: Note their incompatibility.
	Fixes RH#187847.

strace.1

@@ -220,7 +220,8 @@ Here the second argument represents the full set of all signals.
 .B \-c
 Count time, calls, and errors for each system call and report a summary on
 program exit.  On Linux, this attempts to show system time (CPU time spent
-running in the kernel) independent of wall clock time.
+running in the kernel) independent of wall clock time.  If -c is used with
+-f or -F (below), only aggregate totals for all traced processes are kept.
 .TP
 .B \-d
 Show some debugging output of
@@ -254,6 +255,7 @@ If the
 option is in effect, each processes trace is written to
 .I filename.pid
 where pid is the numeric process id of each process.
+This is incompatible with -c, since no per-process counts are kept.
 .TP
 .B \-F
 Attempt to follow

strace.c

@@ -314,6 +314,13 @@ char *argv[];
 	if ((optind == argc) == !pflag_seen)
 		usage(stderr, 1);
 
+	if (followfork > 1 && cflag) {
+		fprintf(stderr,
+			"%s: -c and -ff are mutually exclusive options\n",
+			progname);
+		exit(1);
+	}
+
 	/* See if they want to run as another user. */
 	if (username != NULL) {
 		struct passwd *pent;