diff --git a/LSL.cs b/LSL.cs
index bb7137d..6dfc17a 100644
--- a/LSL.cs
+++ b/LSL.cs
@@ -611,11 +611,16 @@ public double pull_sample(string[] sample, double timeout = LSL.FOREVER)
             double res = dll.lsl_pull_sample_str(obj, tmp, tmp.Length, timeout, ref ec); LSL.check_error(ec);
             try
             {
-                for (int k = 0; k < tmp.Length; k++)
-                    sample[k] = Marshal.PtrToStringAnsi(tmp[k]);
+                // liblsl >= 1.18 leaves tmp untouched (all null) when no sample was available (res == 0.0);
+                // in that case leave the caller's array untouched too, like the numeric overloads do.
+                if (res != 0.0)
+                    for (int k = 0; k < tmp.Length; k++)
+                        sample[k] = Marshal.PtrToStringAnsi(tmp[k]);
             }
             finally
             {
+                // lsl_destroy_string is null-safe; always free so older liblsl versions
+                // (which allocate empty strings on timeout) don't leak.
                 for (int k = 0; k < tmp.Length; k++)
                     dll.lsl_destroy_string(tmp[k]);
             }