diff --git a/libbacktrace/BacktraceOffline.cpp b/libbacktrace/BacktraceOffline.cpp
index 9a4f622..c2b68bc 100644
--- a/libbacktrace/BacktraceOffline.cpp
+++ b/libbacktrace/BacktraceOffline.cpp
@@ -665,7 +665,7 @@
 
 class ScopedZiparchiveHandle {
  public:
-  ScopedZiparchiveHandle(ZipArchiveHandle handle) : handle_(handle) {
+  explicit ScopedZiparchiveHandle(ZipArchiveHandle handle) : handle_(handle) {
   }
 
   ~ScopedZiparchiveHandle() {