diff --git a/uv-unix.c b/uv-unix.c
index b0e85d95..4163683c 100644
--- a/uv-unix.c
+++ b/uv-unix.c
@@ -122,7 +122,7 @@ static uv_err_t uv_err_new(uv_handle_t* handle, int sys_error) {
 }
 
 
-struct sockaddr_in uv_ip4_addr(char* ip, int port) {
+struct sockaddr_in uv_ip4_addr(const char* ip, int port) {
   struct sockaddr_in addr;
 
   addr.sin_family = AF_INET;
diff --git a/uv-win.c b/uv-win.c
index 6a42b4d4..e9e1bbb6 100644
--- a/uv-win.c
+++ b/uv-win.c
@@ -705,7 +705,7 @@ int uv_close(uv_handle_t* handle, uv_close_cb close_cb) {
 }
 
 
-struct sockaddr_in uv_ip4_addr(char* ip, int port) {
+struct sockaddr_in uv_ip4_addr(const char* ip, int port) {
   struct sockaddr_in addr;
 
   addr.sin_family = AF_INET;
diff --git a/uv.h b/uv.h
index 491e4676..2806cc29 100644
--- a/uv.h
+++ b/uv.h
@@ -367,7 +367,7 @@ int64_t uv_now();
 
 
 /* Utility */
-struct sockaddr_in uv_ip4_addr(char* ip, int port);
+struct sockaddr_in uv_ip4_addr(const char* ip, int port);
 
 /* Gets the executable path */
 int uv_get_exepath(char* buffer, size_t* size);