Macro which will not compile the function if not defined

Question

Currently using to show debug output when in debug mode:

#ifdef _DEBUG
#define printX(...) Serial.printf( __VA_ARGS__ )
#else
#define printX(...) NULL
#endif

yet this still include the printX in the result code, and the parameters which have been applied still consume memory, cpu power, and stack size, so my question is:

is there a way to have a macro, which is not including the function, and "ignoring" all of it's calls in the source when in "release mode" and basically not compile anything with it ?

What do you mean by "still include the `printX` in the result code"? In the `else` branch, `printX(...)` with all its arguments is replaced with `NULL`. — Evg, Jul 04 '21 at 07:32
Right... my stack went overflow then :D Thank You for the fast resetting it ! — Yordan Yanakiev, Jul 04 '21 at 07:38
@Evg please put it as an answer so I can accept it since it's correct one. — Yordan Yanakiev, Jul 05 '21 at 05:50

score 2 · Answer 1 · answered Jul 04 '21 at 10:35

2

A macro is a not a function. It does not consume any memory, cpu power, or stack size. This is because macros operate entirely at compile time, and just act as a text replacing mechanism. When the program is run, there are no macros which are "called".

answered Jul 04 '21 at 10:35

SomeProgrammer

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score 1 · Answer 2 · answered Jul 04 '21 at 16:00

In my programs I include a line that says:

#define DEBUG_MODE

and I use it anywhere I want to compile with (or without) debug mode:

#ifdef DEBUG_MODE
    print here all the info I need for debug and certainly don't want in released binary.
#endif

Before releasing the final binary I comment out the definition line.

score 1 · Accepted Answer · answered Jul 06 '21 at 06:49

1

The macro

#define printX(...) NULL

replaces printX function call with all its arguments with plain NULL. This is a textual replacement that happens before a compiler is able to take a look at the code, so any nested calls inside printX, e.g.

printX(someExpensiveCall())

will also be completely eliminated.

answered Jul 06 '21 at 06:49

Evg

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Thank You. Sometime really the programmers get "stackoverflow", and my question was a good example of it. :D – Yordan Yanakiev Jul 07 '21 at 07:50

Macro which will not compile the function if not defined

3 Answers3