diff --git a/ptrace/debugger/process.py b/ptrace/debugger/process.py
index bdd79f7..acad8c0 100644
--- a/ptrace/debugger/process.py
+++ b/ptrace/debugger/process.py
@@ -662,7 +662,7 @@ def readCString(self, address, max_size, chunk_length=256):
             if max_size <= size + chunk_length:
                 data = data[:(max_size - size)]
                 string.append(data)
-                truncated = True
+                truncated = (pos == -1)
                 break
             string.append(data)
             if done: