Will #if RELEASE work like #if DEBUG does in C#?

RELEASE is not defined, but you can use

#if (!DEBUG)
  ...
#endif

Nope.

While in debug configuration there is a DEBUG defined constant (automatically defined by Visual Studio) while there is no such constant defined for release mode. Check your project settings under build.

Selecting [Define DEBUG constant] under Project -> Build is like including #define DEBUG at the beginning of every file.

If you want to define a RELEASE constant for the release configuration go to:

• Project Properties -> Build
• Select Release Mode
• in the Conditional compilation symbols textbox enter: RELEASE

No, it won't, unless you do some work.

The important part here is what DEBUG really is, and it's a kind of constant defined that the compiler can check against.

If you check the project properties, under the Build tab, you'll find three things:

• A text box labelled "Conditional compilation symbols"
• A check box labelled "Define DEBUG constant"
• A check box labelled "Define TRACE constant"

There is no such checkbox, nor constant/symbol pre-defined that has the name RELEASE.

However, you can easily add that name to the text box labelled Conditional compilation symbols, but make sure you set the project configuration to Release-mode before doing so, as these settings are per configuration.

So basically, unless you add that to the text box, #if RELEASE won't produce any code under any configuration.