From: Hui Zhu <teawater@antgroup.com>

It is hard to make sure that the process is waiting for the signal
without any output.
This commit add output before sigsuspend in do_units to handle this
issue.

Signed-off-by: Hui Zhu <teawater@antgroup.com>
---
 usemem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/usemem.c b/usemem.c
index 3b4d207..2f100e1 100644
--- a/usemem.c
+++ b/usemem.c
@@ -800,6 +800,8 @@ long do_units(void)
 
 	if (opt_write_signal_read) {
 		sigset_t set;
+		printf("Process %d is waiting signal\n", getpid());
+		fflush(stdout);
 		sigfillset(&set);
 		sigdelset(&set, SIGUSR1);
 		sigsuspend(&set);
-- 
1.8.3.1