diff --git a/gcc/libstdc++-v3/libsupc++/new_opa.cc b/gcc/libstdc++-v3/libsupc++/new_opa.cc
index 29767c1cfa..3c06b5c0bc 100644
--- a/gcc/libstdc++-v3/libsupc++/new_opa.cc
+++ b/gcc/libstdc++-v3/libsupc++/new_opa.cc
@@ -47,7 +47,7 @@ using std::size_t;
 extern "C"
 {
 # if _GLIBCXX_HAVE_POSIX_MEMALIGN
-  void *posix_memalign(void **, size_t alignment, size_t size);
+  int posix_memalign(void **, size_t alignment, size_t size);
 # elif _GLIBCXX_HAVE_ALIGNED_ALLOC
   void *aligned_alloc(size_t alignment, size_t size);
 # elif _GLIBCXX_HAVE__ALIGNED_MALLOC