diff --git a/hydra.h b/hydra.h
index d7ba0a8..1184a00 100644
--- a/hydra.h
+++ b/hydra.h
@@ -1,4 +1,4 @@
-
+#ifndef _HYDRA_H
 
 #include <stdio.h>
 #ifdef __sun
@@ -30,20 +30,20 @@
 #include <errno.h>
 
 #ifdef HAVE_OPENSSL
-#define HYDRA_SSL
+  #define HYDRA_SSL
 #endif
 #ifdef HAVE_SSL
-#ifndef HYDRA_SSL
-#define HYDRA_SSL
-#endif
+  #ifndef HYDRA_SSL
+    #define HYDRA_SSL
+  #endif
 #endif
 
 #ifdef LIBSSH
-#include <libssh/libssh.h>
+  #include <libssh/libssh.h>
 #endif
 
 #ifdef HAVE_ZLIB
-#include <zlib.h>
+  #include <zlib.h>
 #endif
 
 #define OPTION_SSL 1
@@ -148,21 +148,17 @@
 #define True  1
 
 #ifndef INET_ADDRSTRLEN
-#define INET_ADDRSTRLEN 16
+  #define INET_ADDRSTRLEN 16
 #endif
 
 #define MAX_PROXY_COUNT 64
 
 #ifndef _WIN32
-
-int32_t sleepn(time_t seconds);
-int32_t usleepn(long useconds);
-
+  int32_t sleepn(time_t seconds);
+  int32_t usleepn(long useconds);
 #else
-
-int32_t sleepn(uint32_t seconds);
-int32_t usleepn(uint32_t useconds);
-
+  int32_t sleepn(uint32_t seconds);
+  int32_t usleepn(uint32_t useconds);
 #endif
 
 #define _HYDRA_H