From ec4ec91d59b25badf212bf0aee0ad5c1eead7ff1 Mon Sep 17 00:00:00 2001
From: Sebastian Falbesoner <sebastian.falbesoner@gmail.com>
Date: Wed, 11 Mar 2026 17:46:35 +0100
Subject: [PATCH] kernel: doc: explain return value for `btck_WriteBytes`
 callback

This is the only non-void callback type, so it makes sense to document what
implementers should return.
---
 src/kernel/bitcoinkernel.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/kernel/bitcoinkernel.h b/src/kernel/bitcoinkernel.h
index 5427e776177..57c88c1279c 100644
--- a/src/kernel/bitcoinkernel.h
+++ b/src/kernel/bitcoinkernel.h
@@ -349,6 +349,8 @@ typedef void (*btck_ValidationInterfaceBlockDisconnected)(void* user_data, btck_
 
 /**
  * Function signature for serializing data.
+ *
+ * Returns 0 to indicate success.
  */
 typedef int (*btck_WriteBytes)(const void* bytes, size_t size, void* userdata);