I need a way to define a FLAGS_IF macro (or equivalent) such that

FLAGS_IF(expression)
<block_of_code>
FLAGS_ENDIF

when compiling in debug (e.g. with a specific compiler switch) compiles to

if (MyFunction(expression))
{
    <block_of_code>
}

whereas in release does not result in any instruction, just as it was like this

#if 0
    <block_of_code>
#endif

In my ignorance on the matter of c/c++ preprocessors i can't think of any naive way (since #define FLAGS_IF(x) #if 0 does not even compile) of doing this, can you help?

I need a solution that:

• Does not get messed up if */ is present inside <block_of_code>
• Is sure to generate 0 instructions in release even inside inline functions at any depth (i guess this excludes if (false){<block_of_code>} right?)
• Is standard compliant if possible

Thank you