diff --git a/.gitignore b/.gitignore
index 1538c91..2ac5901 100644
--- a/.gitignore
+++ b/.gitignore
@@ -57,6 +57,9 @@ timing.exe
 *.gcno
 *.gcov
 
+coverage/
+coverage*.info
+
 # coverity intermediate directory etc.
 cov-int/
 .coverity_*
diff --git a/build.sh b/build.sh
index 228afff..9338caf 100755
--- a/build.sh
+++ b/build.sh
@@ -24,7 +24,12 @@ if [ -a test ] && [ -f test ] && [ -x test ]; then
       for f in *_tv.txt; do if (diff -i -w -B $f notes/$f) then true; else (echo "tv_gen $f failed" && rm -f testok.txt && exit 1); fi; done
    fi
 fi
+
+lcov_opts="--capture --no-external --directory src -q"
+lcov_out=$(echo coverage_$1_$2_$3 | tr ' -=+' '_')".info"
+
 if [ -a testok.txt ] && [ -f testok.txt ]; then
+   [ "$LTC_COVERAGE" != "" ] && lcov $lcov_opts --output-file $lcov_out
    exit 0
 fi
 exit 1
diff --git a/makefile b/makefile
index 3a96ecf..626da35 100644
--- a/makefile
+++ b/makefile
@@ -275,6 +275,9 @@ profile:
 	rm -f timing `find . -type f | grep [.][ao] | xargs`
 	CFLAGS="$(CFLAGS) -fprofile-use" $(MAKE) timing EXTRALIBS="$(EXTRALIBS) -lgcov"
 
+lcov:
+	lcov `find -name 'coverage_*.info' -exec echo -n " -a {}" \;` -o coverage.info -q 2>/dev/null
+	genhtml coverage.info --output-directory coverage -q
 
 #This rule cleans the source tree of all compiled code, not including the pdf
 #documentation.