How to set dynamically toggle defined macro? - c

Question

Im trying to make my defines can be switched during runtime, so I cant enable/disable printing some info.
I have next files:
main.c
config.c
config.h (included in both c files)
in config.c :
//define DEBUG // <--------------- COMMENT THIS TO SWITCH PRINT/NOT PRINT
#define PRINTF(fmt, ...) printf("TAG: " fmt "\n", ## __VA_ARGS__)
#ifdef DEBUG
#define DPRINTF PRINTF
#else
#define DPRINTF(...) do {} while (0)
#endif
int foo()
{
...
if(error){
PRINTF("error happens, code %d", code);
}
else{
DPRINF("all good, all parameters: [%d][%d]", par1, par2);
}
}
(short explanation: if DEBUG defined then macro DPRINTF will print some info, otherwise do nothing)
What I want is be able to dynamically switch it from main.c somehow, instead of comment / uncomment and recompile program.
So my idea was to set in config.h
extern uint8_t dbg_status;
#define DGB_ON (1)
#define DGB_OFF (0)
#define ENABLE_DBG (dbg_status? (DGB_ON) : (DGB_OFF))
And in main.c do something like that:
uint8_t dbg_status;
int main(int argc, char** argv)
{
// enable debug if run with next argument:
// program.exe -DEBUG
if (!strcmp(argv[1], "-DEBUG"))
{
// enable debug prints
dbg_status= 1;
}
else
{
// disable debug prints
dbg_status= 0;
}
...
}
But Im stuck with it now, I dont know what to do next...
Add some additional defines in config.c?
#if (ENABLE_DEBUG)
#define DEBUG
#endif
I feel that Im on right way, but dont see where to move next.
UPD:
Original idea from here:
Changing a macro at runtime in C
But Im stuck with realization...

Answer 1

You could use something like this:
int debugflag = 0;
void DPRINTF(char *format, ...) {
if (!debugflag)
return;
va_list ap;
va_start(ap, format);
vfprintf(stderr, format, ap);
va_end(ap);
}
Now you can choose dynamically with the global variable debugflag if you want the debug output or not.
With macros, this is not possible directly, since these are evaluated at compile time and cannot be influenced at runtime directly.