diff --git a/src/core/tcp.c b/src/core/tcp.c
index cd4ea31b..57b2a1a9 100644
--- a/src/core/tcp.c
+++ b/src/core/tcp.c
@@ -1302,6 +1302,12 @@ tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr)
 }
 #endif /* TCP_CALCULATE_EFF_SEND_MSS */
 
+const char*
+tcp_debug_state_str(enum tcp_state s)
+{
+  return tcp_state_str[s];
+}
+
 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
 /**
  * Print a tcp header for debugging purposes.
@@ -1339,12 +1345,6 @@ tcp_debug_print(struct tcp_hdr *tcphdr)
   LWIP_DEBUGF(TCP_DEBUG, ("+-------------------------------+\n"));
 }
 
-const char*
-tcp_debug_state_str(enum tcp_state s)
-{
-  return tcp_state_str[s];
-}
-
 /**
  * Print a tcp state for debugging purposes.
  *
diff --git a/src/include/lwip/tcp.h b/src/include/lwip/tcp.h
index 6ce05fd4..2efa0860 100644
--- a/src/include/lwip/tcp.h
+++ b/src/include/lwip/tcp.h
@@ -587,10 +587,10 @@ u16_t tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr);
 extern struct tcp_pcb *tcp_input_pcb;
 extern u32_t tcp_ticks;
 
+const char* tcp_debug_state_str(enum tcp_state s);
 #if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
 void tcp_debug_print(struct tcp_hdr *tcphdr);
 void tcp_debug_print_flags(u8_t flags);
-const char* tcp_debug_state_str(enum tcp_state s);
 void tcp_debug_print_state(enum tcp_state s);
 void tcp_debug_print_pcbs(void);
 s16_t tcp_pcbs_sane(void);