A simple "die" function for C - example of variable number of arguments

This simple function illustrates receiving and sending out a variable number of arguments in C using <stdarg.h>.

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

static void die (int line_number, const char * format, ...)
{
    va_list vargs;
    va_start (vargs, format);
    fprintf (stderr, "%d: ", line_number);
    vfprintf (stderr, format, vargs);
    fprintf (stderr, ".\n");
    va_end (vargs);
    exit (1);
}

int main (int argc, char ** argv)
{
    if (argc == 1) {
	die (__LINE__, "%s: I need more arguments", argv[0]);
    }
    return 0;
}

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The output of this program looks like this:

19: ./die: I need more arguments.

Here is the makefile to compile and run this and print the example:

die.txt: die
        -./die > $@ 2>&1

die: die.c
        cc -Wall -g -o $@ die.c

clean:
        rm -f die die.txt

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