Thread: Defining a macro that takes any number of parameters?

In gcc you can use ... in the macro - this is not portable tho'.

--
Mats

It's portable across C99 compilers.

It's the function prototype that worries me. It uses the ancient, pre-standard varargs technique.

You should #include <stdarg.h> (but only for the implementation) and have this prototype:

Code:

void DTRACE(int level, const char* fmt, ...);

Prior to C99, which makes this easier, you have to use the double parentheses trick.

Code:

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

#if defined( DEBUG ) && defined( ANSI )
void DTRACE_fn ( int level, const char* fmt, ... );
#   define DTRACE( a )  DTRACE_fn a
#else
#   define DTRACE( a )
#endif

void DTRACE_fn ( int level, const char* fmt, ... ) {
    char temp[1000];
    va_list args;
    va_start( args, fmt );
    vsprintf( temp, fmt, args );
    printf("T: &#37;s\n", temp );
    va_end( args );
}

int main ( void ) {
    DTRACE((1,"Hello %s","world"));
    return 0;
}

The extra ( ) make it look like a single parameter to the macro, even though it has embedded commas.