@node vasprintf
@subsection @code{vasprintf}
@findex vasprintf

LSB specification:@* @url{https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/baselib-vasprintf.html}

Documentation:
@itemize
@item
@ifinfo
@ref{Variable Arguments Output,,Variable Arguments Output Functions,libc},
@end ifinfo
@ifnotinfo
@url{https://www.gnu.org/software/libc/manual/html_node/Variable-Arguments-Output.html},
@end ifnotinfo
@item
@uref{https://www.kernel.org/doc/man-pages/online/pages/man3/vasprintf.3.html,,man vasprintf}.
@end itemize

Gnulib module: vasprintf or vasprintf-posix

Portability problems fixed by either Gnulib module @code{vasprintf} or @code{vasprintf-posix}:
@itemize
@item
This function is missing on some platforms:
AIX 5.1, HP-UX 11, IRIX 6.5, Solaris 10, mingw, MSVC 14.
@end itemize

Portability problems fixed by Gnulib module @code{vasprintf-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:
Cygwin 1.5.24.
@item
printf @code{"%f"}, @code{"%e"}, @code{"%g"} of Infinity and NaN yields an
incorrect result on some platforms:
Solaris 11.0.
@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 9.0, OpenBSD 4.0, Solaris 11.4, Cygwin 1.5.x.
@item
This function does not support the @samp{b} directive, required by ISO C23,
on some platforms:
glibc 2.34, musl libc, macOS 12.5, FreeBSD 13.1, NetBSD 9.0, OpenBSD 7.2,
AIX 7.2, Solaris 11.4, Cygwin 2.9.0.
@item
This function does not support the @samp{F} directive on some platforms:
NetBSD 3.0, Cygwin 1.5.x.
@item
This function does not support the @samp{ls} directive on some platforms:
OpenBSD 4.0, Cygwin 1.5.x, Haiku.
@item
This function does not support precisions in the @samp{ls} directive correctly
on some platforms:
Solaris 11.4.
@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.
@item
This function doesn't support the @code{'} flag on some platforms:
NetBSD 3.0, Cygwin 1.5.24.
@item
This function does not round the argument of the @samp{a} directive correctly
on some platforms:
Mac OS X 10.12, FreeBSD 13.0.
@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, Solaris 11.0, Cygwin 1.5.x.
@item
This function produces wrong output for the @samp{lc} directive with a NUL
wide character argument on some platforms:
glibc 2.35, FreeBSD 13.1, NetBSD 9.0, OpenBSD 7.2, macOS 12.5, AIX 7.2, Solaris 11.4, and others.
@item
This function can crash in out-of-memory conditions on some platforms:
FreeBSD 13.0, NetBSD 5.0.
@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.
@end itemize