diff --git a/README.md b/README.md
index ffb6da30..a61dc036 100644
--- a/README.md
+++ b/README.md
@@ -273,6 +273,7 @@ void async_example()
 ---
 #### Asynchronous logger with multi sinks
 ```c++
+#include "spdlog/async.h"
 #include "spdlog/sinks/stdout_color_sinks.h"
 #include "spdlog/sinks/rotating_file_sink.h"
 
diff --git a/include/spdlog/common.h b/include/spdlog/common.h
index 1269c14a..26d3708e 100644
--- a/include/spdlog/common.h
+++ b/include/spdlog/common.h
@@ -319,7 +319,7 @@ struct source_loc {
           line{line_in},
           funcname{funcname_in} {}
 
-    SPDLOG_CONSTEXPR bool empty() const SPDLOG_NOEXCEPT { return line == 0; }
+    SPDLOG_CONSTEXPR bool empty() const SPDLOG_NOEXCEPT { return line <= 0; }
     const char *filename{nullptr};
     int line{0};
     const char *funcname{nullptr};