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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