C++ 14

---

Deprecated

We can place this attribute before a function and a compile time warning will appear.

File: depr1.cpp

#include <iostream>
#include <type_traits>

[[deprecated]]
void old_method1()
{
}

[ [deprecated("Use new_method instead")] ]
void old_method2()
{
}


int main()
{
  old_method1() ;
  old_method2() ;

  return 0;
}

$ g++ depr1.cpp ; ./a.exe
depr1.cpp: In function ‘int main()’:
depr1.cpp:17:14: warning: ‘void old_method1()’ is deprecated [-Wdeprecated-declarations]
   17 |   old_method1() ;
      |   ~~~~~~~~~~~^~
depr1.cpp:5:6: note: declared here
    5 | void old_method1()
      |      ^~~~~~~~~~~
depr1.cpp:18:14: warning: ‘void old_method2()’ is deprecated: Use new_method instead [-Wdeprecated-declarations]
   18 |   old_method2() ;
      |   ~~~~~~~~~~~^~
depr1.cpp:10:6: note: declared here
   10 | void old_method2()
      |      ^~~~~~~~~~~

Note that if the function is not called/used then the warnings do not appear.