diff --git a/src/core/tcp_out.c b/src/core/tcp_out.c
index d6622178..b9fc339e 100644
--- a/src/core/tcp_out.c
+++ b/src/core/tcp_out.c
@@ -1377,9 +1377,9 @@ void
 tcp_keepalive(struct tcp_pcb *pcb)
 {
   struct pbuf *p;
-#if CHECKSUM_GEN_TCP
+#if CHECKSUM_GEN_TCP
   struct tcp_hdr *tcphdr;
-#endif /* CHECKSUM_GEN_TCP */
+#endif /* CHECKSUM_GEN_TCP */
 
   LWIP_DEBUGF(TCP_DEBUG, ("tcp_keepalive: sending KEEPALIVE probe to "));
   ipX_addr_debug_print(PCB_ISIPV6(pcb), TCP_DEBUG, &pcb->remote_ip);
@@ -1394,12 +1394,12 @@ tcp_keepalive(struct tcp_pcb *pcb)
                 ("tcp_keepalive: could not allocate memory for pbuf\n"));
     return;
   }
-#if CHECKSUM_GEN_TCP
+#if CHECKSUM_GEN_TCP
   tcphdr = (struct tcp_hdr *)p->payload;
 
   tcphdr->chksum = ipX_chksum_pseudo(PCB_ISIPV6(pcb), p, IP_PROTO_TCP, p->tot_len,
       &pcb->local_ip, &pcb->remote_ip);
-#endif /* CHECKSUM_GEN_TCP */
+#endif /* CHECKSUM_GEN_TCP */
   TCP_STATS_INC(tcp.xmit);
 
   /* Send output to IP */
diff --git a/src/include/lwip/tcp.h b/src/include/lwip/tcp.h
index 0ab301f0..add77e8d 100644
--- a/src/include/lwip/tcp.h
+++ b/src/include/lwip/tcp.h
@@ -233,7 +233,7 @@ struct tcp_pcb {
 
   u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
 #define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3)
-  u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
+  u16_t snd_queuelen; /* Available buffer space for sending (in pbufs). */
 
 #if TCP_OVERSIZE
   /* Extra bytes available at the end of the last pbuf in unsent. */