core/tun.c: Fix wrong documentation ret type in tundev_open_fd()

Change-Id: I208821cf216c2a700caf6517a885cf44fc6958e1
---
M src/core/tun.c
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/tun.c b/src/core/tun.c
index 04a1972..28cec34 100644
--- a/src/core/tun.c
+++ b/src/core/tun.c
@@ -268,7 +268,7 @@
 /*! Open and configure fd of the tunnel device.
  *  \param[in] tundev The tundev object whose tunnel interface to open
  *  \param[in] flags internal linux flags to pass when creating the device (not used yet)
- *  \returns 0 on success; negative on error
+ *  \returns tun fd on success; negative on error
  */
 static int tundev_open_fd(struct osmo_tundev *tundev, int flags)
 {

