compiling FreeBSD date on Linux

[francis keyes]

I patched date.c and tried to compile but I get a few errors, as you
suspected:

In file included from date.c:59:
vary.h:35: warning: ‘struct tm’ declared inside parameter list
vary.h:35: warning: its scope is only this definition or declaration, which
is probably not what you want
date.c: In function ‘main’:
date.c:85: error: storage size of ‘lt’ isn’t known
date.c:163: error: invalid type argument of ‘unary *’ (have ‘int’)
date.c:172: warning: incompatible implicit declaration of built-in function
‘strftime’
date.c: In function ‘setthetime’:
date.c:190: warning: assignment makes pointer from integer without a cast
date.c:191: warning: assignment makes pointer from integer without a cast
date.c:211: warning: assignment makes pointer from integer without a cast
date.c:217: error: dereferencing pointer to incomplete type
date.c:218: error: dereferencing pointer to incomplete type
date.c:221: error: dereferencing pointer to incomplete type
date.c:227: error: dereferencing pointer to incomplete type
date.c:232: error: dereferencing pointer to incomplete type
date.c:234: error: dereferencing pointer to incomplete type
date.c:235: error: dereferencing pointer to incomplete type
date.c:236: error: dereferencing pointer to incomplete type
date.c:238: error: dereferencing pointer to incomplete type
date.c:242: error: dereferencing pointer to incomplete type
date.c:243: error: dereferencing pointer to incomplete type
date.c:245: error: dereferencing pointer to incomplete type
date.c:248: error: dereferencing pointer to incomplete type
date.c:249: error: dereferencing pointer to incomplete type
date.c:253: error: dereferencing pointer to incomplete type
date.c:254: error: dereferencing pointer to incomplete type
date.c:258: error: dereferencing pointer to incomplete type
date.c:259: error: dereferencing pointer to incomplete type
date.c:268: error: dereferencing pointer to incomplete type


On Wed, May 20, 2009 at 4:20 PM, Roland Smith <rsmith at xs4all.nl> wrote:

> On Wed, May 20, 2009 at 02:45:59PM -0300, francis keyes wrote:
> > Hmm... the date program looks pretty simple but I don't understand the
> > Makfile:
> >
> > #    @(#)Makefile    8.1 (Berkeley) 5/31/93
> > # $FreeBSD: src/bin/date/Makefile,v 1.11.30.1 2009/04/15 03:14:26
> kensmith
> > Exp $
> >
> > PROG=    date
> > SRCS=    date.c netdate.c vary.c
> > DPADD=    ${LIBUTIL}
> > LDADD=    -lutil
> >
> > .include <bsd.prog.mk>
> >
> >
> > Would it be possible to compile this without a makefile?
>
> Sure. A command like "gcc -o date date.c netdate.c vary.c" works,
> provided you patch date.c to remove the dependency on libutil (logwtmp
> function). This will stop date from logging to wtmp(5).
>
> ----- patch for date.c -----
> --- date.c.orig 2009-05-04 22:09:01.000000000 +0200
> +++ date.c      2009-05-20 21:05:32.000000000 +0200
> @@ -48,7 +48,7 @@
>  #include <ctype.h>
>  #include <err.h>
>  #include <locale.h>
> -#include <libutil.h>
> +/*#include <libutil.h>*/
>  #include <stdio.h>
>  #include <stdlib.h>
>  #include <string.h>
> @@ -274,12 +274,12 @@
>        if (!jflag) {
>                /* set the time */
>                if (nflag || netsettime(tval)) {
> -                       logwtmp("|", "date", "");
> +                       /*logwtmp("|", "date", "");*/
>                        tv.tv_sec = tval;
>                        tv.tv_usec = 0;
>                        if (settimeofday(&tv, (struct timezone *)NULL))
>                                err(1, "settimeofday (timeval)");
> -                       logwtmp("{", "date", "");
> +                       /*logwtmp("{", "date", "");*/
>                }
>
>                if ((p = getlogin()) == NULL)
> ----- patch for date.c -----
>
> With this patch, the executable only depends on libc.
>
> Note that I have only confirmed that it compiles _on FreeBSD_. There
> might be additional differences between FreeBSD libc and the GNU libc
> that is used on Linux that make further tinkering with the source
> necessary.
>
> Roland
> --
> R.F.Smith                                   http://www.xs4all.nl/~rsmith/<http://www.xs4all.nl/%7Ersmith/>
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