diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 1e5a507..c2965e9 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -42,12 +42,12 @@
 #define MBEDTLS_ERR_GCM_HW_ACCEL_FAILED                   -0x0013  /**< GCM hardware accelerator failed. */
 #define MBEDTLS_ERR_GCM_BAD_INPUT                         -0x0014  /**< Bad input parameters to function. */
 
-#if !defined(MBEDTLS_GCM_ALT)
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
+#if !defined(MBEDTLS_GCM_ALT)
+
 /**
  * \brief          The GCM context structure.
  */
@@ -66,6 +66,10 @@
 }
 mbedtls_gcm_context;
 
+#else  /* !MBEDTLS_GCM_ALT */
+#include "gcm_alt.h"
+#endif /* !MBEDTLS_GCM_ALT */
+
 /**
  * \brief           This function initializes the specified GCM context,
  *                  to make references valid, and prepares the context
@@ -236,18 +240,6 @@
  */
 void mbedtls_gcm_free( mbedtls_gcm_context *ctx );
 
-#ifdef __cplusplus
-}
-#endif
-
-#else  /* !MBEDTLS_GCM_ALT */
-#include "gcm_alt.h"
-#endif /* !MBEDTLS_GCM_ALT */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /**
  * \brief          The GCM checkup routine.
  *