From 7f143a83c1a1b9b3654d2f3cfeab4f9e6362f1f4 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Wed, 14 Nov 2018 10:06:27 +0100
Subject: [PATCH] output/alsa: fix wrong use of `errno`

alsa-lib doesn't set errno, it returns errors as negative integers.
---
 src/output/plugins/AlsaOutputPlugin.cxx | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/output/plugins/AlsaOutputPlugin.cxx b/src/output/plugins/AlsaOutputPlugin.cxx
index 01ad5e356..8932a02fb 100644
--- a/src/output/plugins/AlsaOutputPlugin.cxx
+++ b/src/output/plugins/AlsaOutputPlugin.cxx
@@ -727,7 +727,7 @@ AlsaOutput::DrainInternal()
 	/* drain period_buffer */
 	if (!period_buffer.IsEmpty()) {
 		auto frames_written = WriteFromPeriodBuffer();
-		if (frames_written < 0 && errno != EAGAIN) {
+		if (frames_written < 0 && frames_written != -EAGAIN) {
 			CancelInternal();
 			return true;
 		}