view doc/posix-functions/vfprintf.texi @ 17927:b941bb9e9efb

printf, isinf, etc.: noncanonical != NaN Do not require that isinf, printf, etc. treat noncanonical values as NaNs. Instead, require only that they do not crash. Problem reported by Joseph Myers in: https://sourceware.org/ml/libc-alpha/2015-02/msg00244.html * doc/posix-functions/dprintf.texi (dprintf): * doc/posix-functions/fprintf.texi (fprintf): * doc/posix-functions/isfinite.texi (isfinite): * doc/posix-functions/isinf.texi (isinf): * doc/posix-functions/isnan.texi (isnan): * doc/posix-functions/printf.texi (printf): * doc/posix-functions/snprintf.texi (snprintf): * doc/posix-functions/sprintf.texi (sprintf): * doc/posix-functions/vdprintf.texi (vdprintf): * doc/posix-functions/vfprintf.texi (vfprintf): * doc/posix-functions/vprintf.texi (vprintf): * doc/posix-functions/vsnprintf.texi (vsnprintf): * doc/posix-functions/vsprintf.texi (vsprintf): Document this. * m4/isfinite.m4 (gl_ISFINITEL_WORKS): * m4/isinf.m4 (gl_ISINFL_WORKS): * m4/isnanl.m4 (gl_FUNC_ISNANL_WORKS): * m4/printf.m4 (gl_PRINTF_INFINITE_LONG_DOUBLE): * tests/test-isfinite.c (test_isfinitel): * tests/test-isinf.c (test_isinfl): * tests/test-isnan.c (test_long_double): * tests/test-isnanl.h (main): * tests/test-snprintf-posix.h (test_function): * tests/test-sprintf-posix.h (test_function): * tests/test-vasnprintf-posix.c (test_function): * tests/test-vasprintf-posix.c (test_function): o Test only that noncanonical values do not cause crashes, not that they are treated as NaNs. In some cases this means a larger output buffer is needed.
author Paul Eggert <eggert@cs.ucla.edu>
date Fri, 20 Feb 2015 18:09:47 -0800
parents 498a2211d839
children
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@node vfprintf
@section @code{vfprintf}
@findex vfprintf

POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/vfprintf.html}

Gnulib module: vfprintf-posix or stdio, nonblocking, sigpipe

Portability problems fixed by Gnulib module @code{vfprintf-posix}:
@itemize
@item
This function does not support size specifiers as in C99 (@code{hh}, @code{ll},
@code{j}, @code{t}, @code{z}) on some platforms:
AIX 5.1, HP-UX 11.23, IRIX 6.5, OSF/1 5.1, Solaris 9, Cygwin 1.5.24, mingw, MSVC 9, BeOS.
@item
printf of @samp{long double} numbers is unsupported on some platforms:
mingw, MSVC 9, BeOS.
@item
printf @code{"%f"}, @code{"%e"}, @code{"%g"} of Infinity and NaN yields an
incorrect result on some platforms:
AIX 5.2, OSF/1 5.1, Solaris 11 2011-11, mingw, MSVC 9.
@item
This function does not support the @samp{a} and @samp{A} directives on some
platforms:
glibc-2.3.6, Mac OS X 10.5, NetBSD 5.0, OpenBSD 4.0, AIX 5.2, HP-UX 11,
IRIX 6.5, OSF/1 5.1, Solaris 11 2011-11, Cygwin 1.5.x, mingw, MSVC 9, BeOS.
@item
This function does not support the @samp{F} directive on some platforms:
NetBSD 3.0, AIX 5.1, HP-UX 11.23, IRIX 6.5, OSF/1 5.1, Solaris 9,
Cygwin 1.5.x, mingw, MSVC 9, BeOS.
@item
This function does not support the @samp{n} directive on some platforms:
MSVC 9.
@item
This function does not support the @samp{ls} directive on some platforms:
OpenBSD 4.0, IRIX 6.5, Solaris 2.6, Cygwin 1.5.x, Haiku.
@item
This function does not support precisions in the @samp{ls} directive correctly
on some platforms:
Solaris 11 2011-11.
@item
This function does not support format directives that access arguments in an
arbitrary order, such as @code{"%2$s"}, on some platforms:
NetBSD 3.0, mingw, MSVC 9, BeOS.
@item
This function doesn't support the @code{'} flag on some platforms:
NetBSD 3.0, Cygwin 1.5.24, mingw, MSVC 9.
@item
This function behaves incorrectly when a @samp{-} flag and a negative width
are specified together, on some platforms:
HP-UX 10.20.
@item
printf @code{"%010f"} of NaN and Infinity yields an incorrect result (padded
with zeroes) on some platforms:
Mac OS X 10.5, FreeBSD 6.0, NetBSD 5.0, AIX 5.2, IRIX 6.5, OSF/1 5.1, Solaris 11 2011-11, Cygwin 1.5.x, mingw, MSVC 9.
@item
This function does not support precisions larger than 512 or 1024 in integer,
floating-point and pointer output on some platforms:
AIX 7.1, Solaris 10/x86, mingw, MSVC 9, BeOS.
@item
This function mishandles large floating point precisions
(for example, formatting 1.0 with @samp{"%.511f"})
on some platforms:
Solaris 10.
@item
This function can crash in out-of-memory conditions on some platforms:
Mac OS X 10.3, FreeBSD 6.0, NetBSD 5.0.
@end itemize

Portability problems fixed by Gnulib module @code{stdio} or @code{vfprintf-posix}, together with module @code{nonblocking}:
@itemize
@item
When writing to a non-blocking pipe whose buffer is full, this function fails
with @code{errno} being set to @code{ENOSPC} instead of @code{EAGAIN} on some
platforms:
mingw, MSVC 9.
@end itemize

Portability problems fixed by Gnulib module @code{stdio} or @code{vfprintf-posix}, together with module @code{sigpipe}:
@itemize
@item
When writing to a pipe with no readers, this function fails, instead of
obeying the current @code{SIGPIPE} handler, on some platforms:
mingw, MSVC 9.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
Formatting noncanonical @samp{long double} numbers produces
nonmeaningful results on some platforms:
glibc and others, on x86, x86_64, IA-64 CPUs.
@item
When formatting an integer with grouping flag, this function inserts thousands
separators even in the "C" locale on some platforms:
NetBSD 5.1.
@item
Attempting to write to a read-only stream fails with @code{EOF} but
does not set the error flag for @code{ferror} on some platforms:
glibc 2.13, cygwin 1.7.9.
@end itemize