diff --git a/leaks.awk b/leaks.awk
new file mode 100644
index 00000000..1d19ea88
--- /dev/null
+++ b/leaks.awk
@@ -0,0 +1,56 @@
+# 7 april 2015
+
+$2 == "alloc" {
+	if ($1 in A) {
+		problem($1 " already allocated (" A[$1] "); allocated at " NR)
+		next
+	}
+	A[$1] = type()
+	next
+}
+
+$2 == "realloc" {
+	if (!($1 in A)) {
+		problem($1 " not yet allocated; reallocated at " NR)
+		next
+	}
+	if ($3 in A) {
+		problem($3 " already allocated (" A[$3] "); reallocated at " NR)
+		next
+	}
+	t = A[$1]
+	delete A[$1]
+	A[$3] = t
+	next
+}
+
+$2 == "free" {
+	if (!($1 in A)) {
+		problem($1 " not yet allocated; freed at " NR)
+		next
+	}
+	delete A[$1]
+	next
+}
+
+{ problem("unrecognized line " $0 " at " NR) }
+
+END {
+	for (i in A)
+		problem("leaked " A[i] " at " i)
+	close("/dev/stderr")
+	if (hasProblems)
+		exit 1
+}
+
+function problem(s) {
+	print s > "/dev/stderr"
+	hasProblems = 1
+}
+
+function type(		s, i) {
+	s = $3
+	for (i = 4; i <= NF; i++)
+		s = s " " $i
+	return s
+}