[[deprecated]] results in error instead of warning in Visual Studio

Question

According to cppreference [[deprecated("message string")]] we should be able to use the symbol but in VS results in error instead.

For example I wan't to issue a warning for ANSI methods in UNICODE builds and vice versa:

#ifdef UNICODE
[[deprecated("This method does not work well in UNICODE builds")]]
#endif // UNICODE
    void f() {}

compiler doesn't let me compile, but standard says the attribute should allow usage but issue a warning message.

How to resolve this?, btw. my project is set to maximum conformance with the standard.

What ever the reason for VS going against the standard, is there a better way to issue a warning for above case?

Answer 1

Very much late to the party, but this cost me a couple of hours this morning.

By default, Visual Studio and the sdl (Security Development Lifecycle) compile flag treat [[deprecated]] as an error. Whether or not you agree with this or not, that's how they do it.

To fix this go to Configuration Properties -> C/C++ -> Command Line and add /sdl /w34996

The /wX part represents the severity of the warning, and the rest is the error you want to report as a warning.

I hope this saves people some time.

Answer 2

I was able to get the compiler to treat [[deprecated]] as a warning by adding

/w34996

to the compiler options, as suggested in the responses in following link

https://developercommunity.visualstudio.com/content/problem/786502/cant-treat-deprecated-warning-as-warning-with-wx.html

Answer 3

is there a better way to issue a warning for above case?

There's no other way of warning about usage of a function than deprecation attribute in standard C++ at least that I know of.

Msvc has other alternatives such as #pragma deprecated(f), but those are not better.

How to resolve this?

Assuming you haven't configured your compiler to treat warnings as errors, you could proceed with writing a bug report to the maintainers.