Changes between Version 1 and Version 2 of Programming/Cpp/StandardLibraryGotchaIncludeHeadersExplicitly

Timestamp:

Feb 19, 2016, 4:09:42 PM (8 years ago)

Author:

Vijay Varadan

Comment:

--

Programming/Cpp/StandardLibraryGotchaIncludeHeadersExplicitly

@@ -4 +4 @@
 [[Image(htdocs:images/cpp/tcpppl.jpg, alt="tcpppl", align=center)]]
 
-I was using the `boost::log` library component and when compiling my code, I ran into a rather odd error converting a derived shared pointer to a base class shared pointer, i.e. implicitly converting a **`shared_ptr<std::ofstream>`** to a **`const shared_ptr<std::ostream> &amp;`**. Here's the code snippet, with the line causing the compiler error highlighed. Note that code has been simplified for clarity.
+I was using the `boost::log` library component and when compiling my code, I ran into a rather odd error converting a derived shared pointer to a base class shared pointer, i.e. implicitly converting a **`shared_ptr<std::ofstream>`** to a **`const shared_ptr<std::ostream> &`**. Here's the code snippet, with the line causing the compiler error highlighed. Note that code has been simplified for clarity.
 
 {{{#!cpp
@@ -12 +12 @@
     sinks::text_ostream_backend> TextSink;
 
-bool Initialize(const std::string &amp;logFile)
+bool Initialize(const std::string &logFile)
 {
-    bool didSucceed = false;
+    bool didSucceed = false;
 
     try
     {
-        auto sink = boost::make_shared<TextSink>();
-        auto lfstream 
-            = boost::make_shared<std::ofstream>(logFile);
+        auto sink = boost::make_shared<TextSink>();
+        auto lfstream
+            = boost::make_shared<std::ofstream>(logFile);
         sink->locked_backend()->add_stream(lfstream); // <-- COMPILER ERROR HERE
         core::get()->add_sink(sink);
-        BOOST_LOG(lgr_gtl) << "LogSystem initialized...";
+        BOOST_LOG(lgr_gtl) << "LogSystem initialized...";
         core::get()->flush();
  
-        didSucceed = true;
+        didSucceed = true;
     }
-    catch (const std::exception& ex)
+    catch (const std::exception& ex)
     {
         std::cout
-            << "LogSystem::Initialize() failed."
-            << std::endl;
-        std::cout << "Details:" << std::endl;
-        std::cout << ex.what() << std::endl;
+            << "LogSystem::Initialize() failed."
+            << std::endl;
+        std::cout << "Details:" << std::endl;
+        std::cout << ex.what() << std::endl;
     }
-    return didSucceed;
+    return didSucceed;
 }
 }}}
@@ -43 +43 @@
 the comment `COMPILER ERROR HERE`:
 
-{{{#!cpp
-error C2664: 'void boost::log::v2s_mt_nt6::sinks::basic_text_ostream_backend<char>::add_stream(const boost::shared_ptr<std::basic_ostream<char,std::char_traits<char>>> &amp;)': cannot convert argument 1 from 'boost::shared_ptr<T>' to 'const boost::shared_ptr<std::basic_ostream<char,std::char_traits<char>>> &amp;'
+{{{
+error C2664: 'void boost::log::v2s_mt_nt6::sinks::basic_text_ostream_backend<char>::add_stream(const boost::shared_ptr<std::basic_ostream<char,std::char_traits<char>>> &)': cannot convert argument 1 from 'boost::shared_ptr<T>' to 'const boost::shared_ptr<std::basic_ostream<char,std::char_traits<char>>> &'
     with
     [
@@ -62 +62 @@
 
 {{{#!cpp
-typedef basic_ofstream<char, char_traits<char> > ofstream;
+typedef basic_ofstream<char, char_traits<char> > ofstream;
 }}}
 
@@ -77 +77 @@
 
 {{{#!cpp
-template<class _Elem, class _Traits> class basic_ofstream
-    : public basic_ostream<_Elem, _Traits>
+template<class _Elem, class _Traits> class basic_ofstream
+    : public basic_ostream<_Elem, _Traits>
 { // output stream associated with a C stream
 ...