Remove a function during compile by defining it as an empty macro - c

Question

In this example code a macro is either defined or commented out by the programmer in order to remove a function from the released software.
#include <stdio.h>
#define MACRO //or omitted
#ifdef MACRO
void Function(const char* str)
{
printf("%s\n", str);
}
#else
#define Function(str)
#endif
int main(void)
{
Function("hello world");
getchar();
return 0;
}
Is there anything wrong with this?

Answer 1

Even though your solution works, I prefer the following approach:
#include <stdio.h>
#define MACRO //or omitted
#ifdef MACRO
#define FUNCTION(a) Function(a);
#else
#define FUNCTION(a)
#endif
#ifdef MACRO
void Function(const char* str)
{
printf("%s\n", str);
}
#endif
int main(void)
{
FUNCTION("hello world")
getchar();
return 0;
}
Note: FUNCTION is the macro, Function is the actual name of the function
This works by defining the macro FUNCTION(a) to a call to Function(const char*) when MACRO is enabled. On the other hand, when MACRO is disabled, calls to FUNCTION(a) will be defined to nothing.
I tend to prefer this method since it would be easier to abstract away the macro used to define your call from the macro defining your function definition. You might have cases where in release mode you only need to remove some of the calls to Function. In that case the definition of Function() is still required. For example:
#include <stdio.h>
#define DEBUG //or omitted
#ifdef DEBUG
#define FUNCTION(a) Function(a);
#else
#define FUNCTION(a)
#endif
void Function(const char* str)
{
printf("%s\n", str);
}
int main(void)
{
// Call function with Hello World only in debug
FUNCTION("hello world")
getchar();
// Call function with goodbye world in both debug and release
Function("goodbye world");
return 0;
}

Answer 2

It will work. But the entire symbol is removed this way. I prefer the following method.
#include <stdio.h>
#define MACRO 1
#if MACRO
void Function(const char* str)
{
printf("%s\n", str);
}
#else
void Function(const char *str){}
#endif
int main(void)
{
Function("hello world");
getchar();
return 0;
}
The following has changed:
The #if now compares a boolean. Your IDE is now able to find where MACRO is defined, in all cases. (right click, find definition)
You can, by changing MACRO to 2, change the entire meaning of Function. For example, a release compiled variant might contain a print to file or system log.
There will always be a symbol for Function, even if it does nothing, even in compiled code. This has the benefit that the string literals in the argument still count to the size statistics. As an embedded developer, I find this important.
Obviously, this is partly the preference of the one who crafts the code.