Yes, this really is the classic program that prints “Hello, world!” when you run it. Unlike the elementary version often presented in books like K&R (The C Programming Language), GNU (GNU's Not Unix) hello processes its argument list to modify its behavior, supports internationalization [1], and includes a mail reader.
“hello - GNU Project - Free Software Foundation [2]”
Every program attempts to expand until it can read mail. Those programs which cannot so expand are replaced by ones which can.
“Law of Software Envelopment”
I didn't even realize GNU (GNU's Not Unix) [3] had a “Hello world” program available for downloading, much less one that succumbed to the Law of Software Envelopment. Granted, GNU then goes on to say:
The primary purpose of this program is to demonstrate how to write other programs that do these things; it serves as a model for all of the GNU coding standards [4].
It's quite amusing that GNU can turn this [5]:
#include <stdio.h>
main()
{
printf("hello, world\n");
}
into a 400k compressed download, complete with its own configuration script, m4 macros (who uses m4 anymore?), man pages (and here I thought GNU was big on info pages) along with documentation in TeX [6], plus the various language files for Russian, Slovanian, Japanese and I even think English is included in there somewhere.
Quite amusing.
Note: technically, the code should be written as:
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
printf("hello, world\n");
return(EXIT_SUCCESS);
}
to be fully ANSI (American National Standards Institute) compliant, but hey, who am I to argue with the authors of C?
Then again, if you really want to be anal retentive about it, then:
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
(void)printf("hello, world\n");
return(EXIT_SUCCESS);
}
But that's just being silly …
[1] http://www.gnu.org/prep/standards_25.html#SEC25
[2] http://www.gnu.org/software/hello/hello.html
[4] http://www.gnu.org/prep/standards_toc.html