diff --git a/include/mbedtls/sha1.h b/include/mbedtls/sha1.h
index 05540cd..5fd02d3 100644
--- a/include/mbedtls/sha1.h
+++ b/include/mbedtls/sha1.h
@@ -39,14 +39,14 @@
 
 #define MBEDTLS_ERR_SHA1_HW_ACCEL_FAILED                  -0x0035  /**< SHA-1 hardware accelerator failed */
 
-#if !defined(MBEDTLS_SHA1_ALT)
-// Regular implementation
-//
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_SHA1_ALT)
+// Regular implementation
+//
+
 /**
  * \brief          The SHA-1 context structure.
  *
@@ -63,6 +63,10 @@
 }
 mbedtls_sha1_context;
 
+#else  /* MBEDTLS_SHA1_ALT */
+#include "sha1_alt.h"
+#endif /* MBEDTLS_SHA1_ALT */
+
 /**
  * \brief          This function initializes a SHA-1 context.
  *
@@ -240,18 +244,6 @@
 #undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* MBEDTLS_SHA1_ALT */
-#include "sha1_alt.h"
-#endif /* MBEDTLS_SHA1_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          This function calculates the SHA-1 checksum of a buffer.
  *