Using a character name as a string literal in a #define function macro

Question

I want the debug function macro to work like this:

int myVar = 5;
PRINTVAR(myVar); // macro

// which expands to something like...
print("myVar: ");
println(myVar);

Basically, I want to use the identifier as a string literal as well as a variable.

I'm just a little tired of repeating myself when I want to dump a lot of variables to stdout.

My silly attempt, which of course doesn't work:

#define PRINT_VAR(x) Serial.print("x: "); Serial.println(x);

Is it possible?

+3

aaaidan March 25 At 4:09 am

3 answers

Look at the contraction operator , #, when you use a macro prefix with this, it puts it as a string, not expands it.

+2

gbjbaanb March 25 At 4:16 am

Providing sample code, I don't know if you are talking about C or Java. However, here's what I'll do in C:

#define DEBUG(X, ...) fprintf(x, __VA_ARGS__);

And use it:

DEBUG (srderr, "my mistake \ n");

0

Halim qarroum March 25 At 4:15 am

caf · Accepted Answer · 2012-03-25T04:13:21+0000

The "gating operator" is intended for this very case:

#define PRINT_VAR(x) (print(#x ": "), println(x))