diff --git a/src/api/sockets.c b/src/api/sockets.c
index c39cf921..8b03e8f4 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -993,7 +993,7 @@ int lwip_getsockopt (int s, int level, int optname, void *optval, socklen_t *opt
       /* UNIMPL case SO_SNDBUF: */
       /* UNIMPL case SO_RCVLOWAT: */
       /* UNIMPL case SO_SNDLOWAT: */
-#ifdef SO_REUSE
+#if SO_REUSE
       case SO_REUSEADDR:
       case SO_REUSEPORT:
 #endif /* SO_REUSE */
diff --git a/src/core/tcp.c b/src/core/tcp.c
index 21116569..f7c76572 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -242,7 +242,7 @@ err_t
 tcp_bind(struct tcp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)
 {
   struct tcp_pcb *cpcb;
-#ifdef SO_REUSE
+#if SO_REUSE
   int reuse_port_all_set = 1;
 #endif /* SO_REUSE */
 
diff --git a/src/core/tcp_in.c b/src/core/tcp_in.c
index aab4bc76..f9d5bd8b 100644
--- a/src/core/tcp_in.c
+++ b/src/core/tcp_in.c
@@ -102,7 +102,7 @@ tcp_input(struct pbuf *p, struct netif *inp)
   u8_t hdrlen;
   err_t err;
 
-#ifdef SO_REUSE
+#if SO_REUSE
   struct tcp_pcb *pcb_temp;
   int reuse = 0;
   int reuse_port = 0;
diff --git a/src/core/udp.c b/src/core/udp.c
index 292ff690..4cb25059 100644
--- a/src/core/udp.c
+++ b/src/core/udp.c
@@ -159,7 +159,7 @@ udp_input(struct pbuf *p, struct netif *inp)
   struct ip_hdr *iphdr;
   u16_t src, dest;
 
-#ifdef SO_REUSE
+#if SO_REUSE
   struct udp_pcb *pcb_temp;
   int reuse = 0;
   int reuse_port_1 = 0;