diff --git a/src/conio.h b/src/conio.h
index 8184727..261947f 100644
--- a/src/conio.h
+++ b/src/conio.h
@@ -15,6 +15,11 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef CONIO_H_
 #define CONIO_H_
 
@@ -88,6 +93,10 @@ static inline void printheader(FILE *fp, const char *line, int nl)
 
 #endif /* CONIO_H_ */
 
+#ifdef __cplusplus
+}
+#endif
+
 /**
  * Local Variables:
  *  indent-tabs-mode: t
diff --git a/src/lite.h b/src/lite.h
index 7875661..ea4fdeb 100644
--- a/src/lite.h
+++ b/src/lite.h
@@ -22,6 +22,11 @@
  * THE SOFTWARE.
  */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef LITE_H_
 #define LITE_H_
 
@@ -183,6 +188,10 @@ static inline int fisslashdir(const char *dir)
 
 #endif /* LITE_H_ */
 
+#ifdef __cplusplus
+}
+#endif
+
 /**
  * Local Variables:
  *  indent-tabs-mode: t
diff --git a/src/queue.h b/src/queue.h
index 5e81fdd..c5a867b 100644
--- a/src/queue.h
+++ b/src/queue.h
@@ -32,6 +32,11 @@
  *	@(#)queue.h	8.5 (Berkeley) 8/20/94
  */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef	_SYS_QUEUE_H_
 #define	_SYS_QUEUE_H_
 
@@ -531,3 +536,7 @@ struct {								\
 } while (0)
 
 #endif	/* !_SYS_QUEUE_H_ */
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/strdupa.h b/src/strdupa.h
index ccd177e..3b6cf94 100644
--- a/src/strdupa.h
+++ b/src/strdupa.h
@@ -23,6 +23,12 @@
  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  * ==========================================================================
  */
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef LITE_STRDUPA_H
 #define LITE_STRDUPA_H
 
@@ -50,3 +56,7 @@
 #endif /* !HAVE_STRDUPA */
 
 #endif /* LITE_STRDUPA_H */
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/strlite.h b/src/strlite.h
index dea4a15..519be09 100644
--- a/src/strlite.h
+++ b/src/strlite.h
@@ -21,6 +21,11 @@
  * THE SOFTWARE.
  */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef LITE_STRING_H_
 #define LITE_STRING_H_
 
@@ -106,3 +111,7 @@ static inline int string_case_compare(const char *a, const char *b)
 }
 
 #endif /* LITE_STRING_H_ */
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/strndupa.h b/src/strndupa.h
index 0bfaefd..023694c 100644
--- a/src/strndupa.h
+++ b/src/strndupa.h
@@ -23,6 +23,12 @@
  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  * ==========================================================================
  */
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef LITE_STRNDUPA_H_
 #define LITE_STRNDUPA_H_
 
@@ -51,3 +57,7 @@
 #endif /* !HAVE_STRNDUPA */
 
 #endif /* GNU_STRING_STRNDUPA_H */
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/strnlen.h b/src/strnlen.h
index 5817a60..fc529a7 100644
--- a/src/strnlen.h
+++ b/src/strnlen.h
@@ -15,6 +15,11 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef LITE_STRNLEN_H_
 #define LITE_STRNLEN_H_
 
@@ -41,3 +46,7 @@ static inline size_t xstrnlen(const char *str, size_t lim)
 #endif
 
 #endif /* LITE_STRNLEN_H_ */
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/src/tree.h b/src/tree.h
index e6502b1..974e14b 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -24,6 +24,11 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
 #ifndef	_SYS_TREE_H_
 #define	_SYS_TREE_H_
 
@@ -746,3 +751,7 @@ name##_RB_MINMAX(struct name *head, int val)				\
 	     (x) = (y))
 
 #endif	/* _SYS_TREE_H_ */
+
+#ifdef __cplusplus
+}
+#endif