diff --git a/libshvchainpack/c/include/shv/chainpack/compat.h b/libshvchainpack/c/include/shv/chainpack/compat.h
index 6608846e..b16822dd 100644
--- a/libshvchainpack/c/include/shv/chainpack/compat.h
+++ b/libshvchainpack/c/include/shv/chainpack/compat.h
@@ -3,6 +3,9 @@
 	#if __has_include(<unistd.h>)
 		#include <unistd.h>
 	#endif
+	#if __has_include(<sys/types.h>)
+		#include <sys/types.h>
+	#endif
 #endif
 
 #ifndef __ssize_t_defined