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+Here is how to use gcov to test code coverage in ldb.
+
+Step 1: build ldb with gcov enabled
+
+     make clean all WITH_GCOV=1
+
+Step 3: run the test suite
+     make test-tdb
+
+Step 4: produce the gcov report
+     make gcov
+
+Step 5: read the summary reports
+     less *.report.gcov
+
+Step 6: examine the per-file reports
+     less ldb_tdb\#ldb_tdb.c.gcov
+
+You can also combine steps 2 to 4 like this:
+
+     make clean all test-tdb gcov WITH_GCOV=1
+
+Note that you should not expect 100% coverage, as some error paths
+(such as memory allocation failures) are very hard to trigger. There
+are ways of working around this, but they are quite tricky (they
+involve allocation wrappers that "fork and fail on malloc").
+
+The lines to look for in the per-file reports are the ones starting
+with "#####". Those are lines that are never executed.