(void)0 가 의미하는 바는?

int main(int argc, char *argv[])
{
    int unused_value;
    return 0;
}

[1004 0]# gcc --version
gcc (GCC) 4.1.2 20070925 (Red Hat 4.1.2-27)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
root@ktdserver:~
[1005 0]# gcc -Wall -W a.c
a.c: In function 'main':
a.c:7: warning: unused variable 'unused_value'
a.c: At top level:
a.c:5: warning: unused parameter 'argc'
a.c:5: warning: unused parameter 'argv'

int main(int argc, char *argv[])
{
    int unused_value;
 
    (void)argc;
    (void)argv;
    (void)unused_value;
    return 0;
}