@node mbstowcs
@subsection @code{mbstowcs}
@findex mbstowcs

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

Gnulib module: mbstowcs
@mindex mbstowcs

Portability problems fixed by Gnulib:
@itemize
@item
In the C or POSIX locales, this function can return @code{(size_t) -1}
and set @code{errno} to @code{EILSEQ}:
@c https://sourceware.org/bugzilla/show_bug.cgi?id=19932
@c https://sourceware.org/bugzilla/show_bug.cgi?id=29511
glibc 2.35.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@item
On Windows and 32-bit AIX platforms, @code{wchar_t} is a 16-bit type and
therefore cannot accommodate all Unicode characters.
@mindex mbstoc32s
However, the Gnulib function @code{mbstoc32s}, provided by Gnulib module
@code{mbstoc32s}, operates on 32-bit wide characters and therefore does not
have this limitation.
@end itemize
