From d763ad6319275e6c142a0917a81d537bb4817446 Mon Sep 17 00:00:00 2001
From: Evgenii Zhemchugov <evgenii.zhemchugov@warwick.ac.uk>
Date: Thu, 3 Aug 2023 15:00:23 +0100
Subject: [PATCH] Logging::operator<<: change argument type from T& to const T&

Non-const references cannot be bound to functions results and literals,
so the code
```C++
Logging log;
try {
  throw std::runtime_error("message");
} catch (std::exception& e) {
  log << e.what() << '\n';
}
```
ends up calling `std::ostream::operator<<` both for `e.what()` and
`'\n'` and produces nothing in the output.
---
 src/Logging/Logging.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Logging/Logging.h b/src/Logging/Logging.h
index 1220078..9b9883f 100644
--- a/src/Logging/Logging.h
+++ b/src/Logging/Logging.h
@@ -189,7 +189,7 @@ class Logging: virtual public std::ostream {
    return *this;
  }
  
- template<typename T>  Logging& operator<<(T &a){
+ template<typename T>  Logging& operator<<(const T &a){
      
    std::cout.rdbuf(buffer);
    std::cout<<a;