Why does my variadic macro throw an error when nothing is passed?

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Title: Why does my variadic macro throw an error when nothing is passed?

Body:

I’m trying to create a C program that takes multiple integers as input via the print(...) macro, without needing to pass the length of arguments manually from the main function. To achieve this, I implemented a macro to automatically determine the number of arguments passed and then print them.

Here’s the code:

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

void function_for_printing(int len, ...)
{
    va_list args;
    va_start(args, len);
    if (len > 0)
    {
        for (int i = 0; i < len; i++)
        {
            int temp = va_arg(args, int);
            printf("%d ", temp);
        }
        va_end(args);
        printf("\n");
    }
    else
    {
        va_end(args);
        printf("\nNothing passed\n");
        return;
    }
    printf("\n");
    return;
}

#define print(...) ({\
    int array[]= {__VA_ARGS__};\
    int size = sizeof(array)/sizeof(array[0]);\
    if(size==0)\
    {\
        function_for_printing(0);\
    }\
    else if (size!=0)\
    {\
        function_for_printing(size, __VA_ARGS__);\
    }\
})

int main()
{
    print(1, 2, 4); // works fine
    print(1, 2, 3, 4, 5, 6, 7); // works fine
    print(); // throws an error

    return 0;
}

My objective:

I want the print(...) macro to:

1. Automatically determine the number of arguments passed (without explicitly passing the size).
2. Print the arguments using function_for_printing(int, ...).
3. If no arguments are passed, the macro should print "Nothing passed" without throwing an error.

Issue:

When no arguments are passed to print(), the program throws an error during compilation. I expected the program to handle an empty input by printing "Nothing passed". I understand that __VA_ARGS__ can cause problems when no arguments are passed.

What I tried:

1. I typecasted __VA_ARGS__ into an int[].
2. I calculated the length using sizeof(array)/sizeof(array[0]).
3. Based on the length, I either pass the arguments to function_for_printing() or call it with 0 if the length is zero.
4. When the length is zero, I wanted it to handle the case gracefully, but the macro doesn’t seem to support empty __VA_ARGS__ as expected.

Question:

How can I modify my code or macro to handle cases where no arguments are passed to print(...) without causing errors?

Any guidance would be appreciated! Thanks in advance.

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