@node vsnprintf
@section @code{vsnprintf}
@findex vsnprintf

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

Gnulib module: vsnprintf or vsnprintf-posix

Portability problems fixed by either Gnulib module @code{vsnprintf} or @code{vsnprintf-posix}:
@itemize
@item
This function is missing on some platforms:
IRIX 5.3, OSF/1 4.0, Solaris 2.5.1.
@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 overwrites memory even when a size argument of 1 is passed on some
platforms:
Linux libc5, BeOS.
@item
This function does not return a byte count as specified in C99 on some
platforms:
HP-UX 11, IRIX 6.5, OSF/1 5.1, Solaris 9, mingw, MSVC 9.
@end itemize

Portability problems fixed by Gnulib module @code{vsnprintf-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, MacOS 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{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 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:
MacOS 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:
MacOS X 10.3, FreeBSD 6.0, NetBSD 5.0.
@item
This function does not truncate the result as specified in C99 on some platforms:
mingw, MSVC 9.
@item
This function does not fully support the @samp{n} directive on some platforms:
HP-UX 11, mingw, MSVC 9.
@item
This function overwrites memory even when a zero size argument is passed on some
platforms:
HP-UX 11, OSF/1 5.1.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
When formatting an integer with grouping flag, this function inserts thousands
separators even in the "C" locale on some platforms:
NetBSD 5.1.
@end itemize
