Date: Tue, 16 Feb 2016 07:48:00 +1100 (EST) From: Bruce Evans <brde@optusnet.com.au> To: "Pedro F. Giffuni" <pfg@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r295631 - head/lib/libc/stdio Message-ID: <20160216073421.B1073@besplex.bde.org> In-Reply-To: <201602151813.u1FIDXAt067326@repo.freebsd.org> References: <201602151813.u1FIDXAt067326@repo.freebsd.org>
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On Mon, 15 Feb 2016, Pedro F. Giffuni wrote:
> Log:
> fputs: Return the number of bytes written.
>
> POSIX.1-2008 requires that successful completion simply return a
> non-negative integer. We have regularly returned a constant value.
> Another, equally valid, implementation convention implies returning
> the number of bytes written.
>
> Adopt this last convention to be in line with what Apple's libc
> does. POSIX also explicitly notes:
>
> Note that this implementation convention cannot be adhered to for strings
> longer than {INT_MAX} bytes as the value would not be representable in the
> return type of the function. For backwards-compatibility, implementations
> can return the number of bytes for strings of up to {INT_MAX} bytes, and
> return {INT_MAX} for all longer strings.
>
> Developers shouldn't depend specifically on either convention but
> the change may help port software from Apple.
>
> Differential Revision: https://reviews.freebsd.org/D442 (Partial)
> Obtained from: Apple Inc. (Libc 997.90.3 with changes)
> Relnotes: yes
>
> Modified:
> head/lib/libc/stdio/fputs.c
>
> Modified: head/lib/libc/stdio/fputs.c
> ==============================================================================
> --- head/lib/libc/stdio/fputs.c Mon Feb 15 17:14:10 2016 (r295630)
> +++ head/lib/libc/stdio/fputs.c Mon Feb 15 18:13:33 2016 (r295631)
> @@ -37,6 +37,7 @@ static char sccsid[] = "@(#)fputs.c 8.1
> __FBSDID("$FreeBSD$");
>
> #include "namespace.h"
> +#include <limits.h>
> #include <stdio.h>
> #include <string.h>
> #include "un-namespace.h"
> @@ -62,5 +63,7 @@ fputs(const char * __restrict s, FILE *
> ORIENT(fp, -1);
> retval = __sfvwrite(fp, &uio);
> FUNLOCKFILE(fp);
> + if (retval == 0)
> + return (iov.iov_len > INT_MAX ? INT_MAX : uio.uio_resid);
> return (retval);
> }
Testing would have shown that this change has no effect except in the
unusual case where iov.iov_len > INT_MAX. uio.resid is always reduced
to 0 if all the output actually worked.
Bruce
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