C言語プログラミング ifdefでデバッグする方法

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

int
main (int argc, char *argv[])
{
	int	i;
	char	*p;

#if EBUG
	printf ("[DEBUG] argc=%d\n", argc);
#endif

#ifdef EBUG
	p = "localhost";
#else
	if (argc != 2) {
		printf ("Usage: a.out hostname\n");
		exit (EXIT_FAILURE);
	}
	p = argv[1];
#endif

	for ( i = 0; i < 10; ++i) {
#ifdef EBUG
		printf ("[DEBUG] i=%d\n", i);
#endif
		printf("%s\n", p);
	}

	exit (EXIT_SUCCESS);
}

gcc -DEBUG ebug.c

実行結果

[DEBUG] argc=1
[DEBUG] i=0
localhost
[DEBUG] i=1
localhost
[DEBUG] i=2
localhost
[DEBUG] i=3
localhost
[DEBUG] i=4
localhost
[DEBUG] i=5
localhost
[DEBUG] i=6
localhost
[DEBUG] i=7
localhost
[DEBUG] i=8
localhost
[DEBUG] i=9
localhost

% gcc ebug.c
% ./a.out
Usage: a.out hostname
1で終了しました
% ./a.out foo
foo
foo
foo
foo
foo
foo
foo
foo
foo
foo