diff -up man-pages-2.80/man3/malloc_hook.3.pom man-pages-2.80/man3/malloc_hook.3
--- man-pages-2.80/man3/malloc_hook.3.pom	2008-06-03 11:50:24.000000000 +0200
+++ man-pages-2.80/man3/malloc_hook.3	2008-06-11 09:20:59.000000000 +0200
@@ -72,6 +72,12 @@ The variable
 points at a function that is called each time after
 .BR sbrk (2)
 was asked for more memory.
+.LP
+Hook variables are not thread-safe so they are deprecated now.
+Programmers should instead preempt callst to the relevant functions
+by defining and exporting functions like "malloc" and "free".
+
+
 .SH "CONFORMING TO"
 These functions are GNU extensions.
 .SH "EXAMPLE"