1 files changed, 1 insertions, 1 deletions
diff --git a/src/nng.h b/src/nng.h
index 1267d0a3..a9357f4a 100644
--- a/src/nng.h
+++ b/src/nng.h
@@ -88,7 +88,7 @@ uint16_t nng_socket_protocol(nng_socket_t);
 /*
  * nng_socket_setopt sets an option for a specific socket.
  */
-NNG_DECL int nng_socket_setopt(nng_socket_t, int, void *, size_t);
+NNG_DECL int nng_socket_setopt(nng_socket_t, int, const void *, size_t);
 
 /*
  * nng_socket_getopt obtains the option for a socket.