perf tools: Introduce usage_with_options_msg()

Now usage_with_options() setup a pager before printing message so normal
printf() or pr_err() will not be shown.  The usage_with_options_msg()
can be used to print some help message before usage strings.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1445701767-12731-4-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/tools/perf/util/parse-options.c b/tools/perf/util/parse-options.c
index eeeed98eb26d..230e771407a3 100644
--- a/tools/perf/util/parse-options.c
+++ b/tools/perf/util/parse-options.c
@@ -760,6 +760,21 @@ void usage_with_options(const char * const *usagestr,
 	exit(129);
 }
 
+void usage_with_options_msg(const char * const *usagestr,
+			    const struct option *opts, const char *fmt, ...)
+{
+	va_list ap;
+
+	exit_browser(false);
+
+	va_start(ap, fmt);
+	strbuf_addv(&error_buf, fmt, ap);
+	va_end(ap);
+
+	usage_with_options_internal(usagestr, opts, 0, NULL);
+	exit(129);
+}
+
 int parse_options_usage(const char * const *usagestr,
 			const struct option *opts,
 			const char *optstr, bool short_opt)