Preprocessor error

Hi,
I have a piece of code as pasted below.

I get warnings like

test1.c:29:32: warning: pasting "(" and ""ERROR:"" does not give a valid preprocessing token
test1.c: In function `main':
test1.c:29: `__MODULE__' undeclared (first use in this function)
test1.c:29: (Each undeclared identifier is reported only once
test1.c:29: for each function it appears in.)

What does warning: pasting "(" and ""ERROR:"" does not give a valid preprocessing token mean?

And where is __MODULE__ defined?

Please provide me some solution.
Taklu.

--------------------------------------------------------
#include <stdio.h>
#include <stdarg.h>

#define DL1 "%s:"
#define DR1 ,__MODULE__
#define DL2 "%d:"
#define DR2 ,__LINE__


void Trace(char *format, ...);

#define Debug(ARGS...) Trace(##ARGS)


#define Error(ARGS,...) \
Debug("ERROR:"DL1 DL2 ARGS "\n" DR1 DR2, ## __VA_ARGS__)


void Trace(char *format, ...){
va_list args;
va_start(args, format);
vprintf(format, args);
va_end(args);
return;
}

main(){
int i = 10;
Error("Print from main");
return 0;
}

I'm curious as to how you managed to post code without seeing this popup.
Please explain.

Quote:

---

Originally Posted by Salem

I'm curious as to how you managed to post code without seeing this popup.
Please explain.

---

My guess would be "disabling JavaScript".

--
Mats

I believe you are trying to implement variadic macros, a C99, objective.


Below code may help in setting that up.

Code:

---


#define debug(args...) if(bug) printf(args)

debug ("starting %s is %s\n", ip_type, start.ip_first);

---

Yeah, the disabling javascript would do the trick

a token is a minimal construct a parser can use to analyse its input, like a name, a number or simply a punctuation character. When you use ## between 2 tokens, the preprocessor expects to get a new valid token, which is not the case with '(' and "Error:". So rework your macros...

you can use __FILE__ __LINE__ __DATE__ __FUNCTION__(c99) and perhaps a few more, but I don't think there is a __MODULE__

Review how you are to actually display this error. Where is your printf?

Quote:

---

Originally Posted by slingerland3g

Review how you are to actually display this error. Where is your printf?

---

Code:

---

vprintf(format, args);

---

perhaps?

--
Mats

Then I would think the order of their #define statement may be the issue. I am not sure on this one.

the definition of Debug(ARGS...) as Trace(##ARGS) makes no sense, that's all.

int main(void)
{
return 0;
}

Like that, Salem? And no. I did NOT Disable JavaScript.

Thanks for the solutions.
The error will be displayed using vprintf.

I did not see the popup while pasting the code.

master5001, the Real issue is with the preprocessor errors.
If you can provide me a solution with that, it would be fine.

Maybe instead of __MODULE__ you could use __FILE__ which translates to the name of the source file [undefined whether that includes the path or not - when I've used it recently, I've got different results from two different compilers recently].

I personally would probably put the commas in the DEBUG macro, rather than in the DR1 and DR2:

Code:

---

...
#define DR1 __MODULE__
....
#define DR2 __LINE__
Debug("ERROR:"DL1 DL2 ARGS "\n", DR1, DR2, ## __VA_ARGS__)

---

--
Mats