Re: gcc not compiling

From: Derek Martin (code_at_pizzashack.org)
Date: 10/31/05

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    Date: Mon, 31 Oct 2005 14:21:23 -0500
To: For users of Fedora Core releases <fedora-list@redhat.com>

    On Mon, Oct 31, 2005 at 11:05:41AM -0800, Brian D. McGrew wrote:
    > Never protoctype main as a void function or else you can't get a return
    > value back to the operating system.

    Sure you can:

            #include <stdio.h>
            void main () {
                    printf("\nHello World!\n");
            }
            $ gcc -o foo foo.c
            foo.c: In function `main':
            foo.c:2: warning: return type of 'main' is not `int'
            $ ./foo
            
            Hello World!
            [ddm@archonis ~]
            $ echo $?
            14
            
    As written, the program returns the value of the last expression
    executed. In this case, printf() printed 14 characters, and the
    program returns that number.

    However, it should be noted that this behavior is not defined by the
    standard, and can't be depended upon. But if you don't want that, no
    problem:

            #include <stdio.h>
            void main(void)
            {
                    Printf("\nHello World!\n");
                    exit(0);
            }
            
            gcc -o foo foo.c
            foo.c: In function `main':
            foo.c:2: warning: return type of 'main' is not `int'
            [ddm@archonis ~]
            $ ./foo
                    
            Hello World!
            [ddm@archonis ~]
            $ echo $?
            0
            
    You can return whatever value you like by calling exit(). 

    -- 
Derek D. Martin
http://www.pizzashack.org/
GPG Key ID: 0x81CFE75D



    


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