diff --git a/man3/posix_memalign.3 b/man3/posix_memalign.3
index e9e5ee62f..925d8a071 100644
--- a/man3/posix_memalign.3
+++ b/man3/posix_memalign.3
@@ -46,6 +46,24 @@ Feature Test Macro Requirements for glibc (see
 .ad l
 .BR posix_memalign ():
 _POSIX_C_SOURCE\ >=\ 200112L || _XOPEN_SOURCE\ >=\ 600
+.sp
+.BR valloc ():
+.br
+.RS 4
+.TP 4
+Since glibc 2.12: 
+.nf
+_BSD_SOURCE ||
+    (_XOPEN_SOURCE >= 500 || 
+        _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&
+    !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
+.br
+.fi
+.TP
+Before glibc 2.12:
+_BSD_SOURCE || _XOPEN_SOURCE >= 500 ||
+_XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED
+.RE
 .ad b
 .SH DESCRIPTION
 The function