@node vdprintf
@subsection @code{vdprintf}
@findex vdprintf

POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/functions/vdprintf.html}

Gnulib module: vdprintf or vdprintf-posix or vdprintf-gnu
@mindex vdprintf
@mindex vdprintf-posix
@mindex vdprintf-gnu

Portability problems fixed by either Gnulib module @code{vdprintf} or @code{vdprintf-posix} or @code{vdprintf-gnu}:
@itemize
@item
This function is missing on some platforms:
Mac OS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, Solaris 11.3, Cygwin 1.5.x, mingw, MSVC 14.
@end itemize

Portability problems fixed by either Gnulib module @code{vdprintf-posix} or @code{vdprintf-gnu}:
@itemize
@item
This function does not support size specifiers as in C23 (@code{w8},
@code{w16}, @code{w32}, @code{w64}, @code{wf8}, @code{wf16}, @code{wf32},
@code{wf64}) on some platforms:
glibc 2.37, musl libc, macOS 14, FreeBSD 13.2, NetBSD 10.0, OpenBSD 7.5, AIX 7.3, Solaris 11.4, Cygwin 3.5.3, mingw, MSVC, Android 9.0.
@item
printf @code{"%f"}, @code{"%e"}, @code{"%g"} of Infinity and NaN yields an
incorrect result on some platforms:
AIX 7.3, Solaris 11.4.
@item
This function doesn't support the @code{'} flag at all on some platforms:
mingw without @code{__USE_MINGW_ANSI_STDIO}, MSVC 14.
@item
This function doesn't support the @code{'} flag correctly for integers
(it uses the decimal point instead of the thousands separator!)
on some platforms:
mingw with @code{__USE_MINGW_ANSI_STDIO}.
@item
This function doesn't support the @code{'} flag together with a precision
on an integer argument correctly on some platforms:
glibc 2.36, FreeBSD 14.0, NetBSD 10.0, Solaris 11, Cygwin 3.6.0, Haiku.
@item
This function doesn't support the @code{'} flag correctly in locales where
the thousands separator is a multibyte character on some platforms:
NetBSD 10.0, Solaris 11 OpenIndiana.
@item
This function does not support the @samp{a} and @samp{A} directives on some
platforms:
Solaris 11.4.
@item
This function does not support the @samp{b} directive, required by ISO C23,
on some platforms:
glibc 2.34, musl libc, macOS 14, FreeBSD 13.2, NetBSD 10.0, OpenBSD 7.5,
AIX 7.3, HP-UX 11, Solaris 11.4, Cygwin 3.5.3, mingw, MSVC 14, Android 9.0.
@item
This function does not support precisions in the @samp{ls} directive correctly
on some platforms:
Solaris 11.4.
@item
This function does not round the argument of the @samp{a} directive correctly
on some platforms:
macOS 14, FreeBSD 14.0, NetBSD 10.0, OpenBSD 7.5, AIX 7.3, Solaris 11.4.
@item
printf @code{"%010f"} of NaN and Infinity yields an incorrect result (padded
with zeroes, or wrong capitalization) on some platforms:
AIX 7.3, Solaris 11.4.
@item
printf @code{"%#.0x"} or @code{"%#.0X"} with a zero argument yields an
incorrect result (non-empty) on some platforms:
Mac OS X 10.6.
@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.
@item
This function produces wrong output for the @samp{lc} directive with a NUL
wide character argument on some platforms:
musl libc 1.2.4.
@end itemize

Portability problems fixed by Gnulib module @code{vdprintf-gnu}:
@itemize
@item
This function does not support the @samp{B} directive on some platforms:
glibc 2.34, musl libc, macOS 14, FreeBSD 13.2, NetBSD 10.0, OpenBSD 7.5, AIX 7.3, Solaris 11.4, Cygwin 3.5.3, mingw, MSVC, Android 9.0.
@end itemize

@mindex printf-with-n-directive
Portability problems fixed by either Gnulib module @code{vdprintf-posix} or @code{vdprintf-gnu}
and additionally the Gnulib module @code{printf-with-n-directive}:
@itemize
@item
This function does not support the @samp{n} directive on some platforms:
glibc when used with @code{_FORTIFY_SOURCE >= 2} (set by default on Ubuntu),
macOS 14, OpenBSD, Android.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
The @code{%m} directive is not portable, use @code{%s} mapped to an
argument of @code{strerror(errno)} (or a version of @code{strerror_r})
instead.
@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
On some platforms, this function does not set @code{errno} or the
stream error indicator on attempts to write to a read-only stream:
Cygwin 1.7.9.
@end itemize
