Re: UTF-8 output via "echo_wchar" resulting in errno=1 on Mac OS X

[Thomas Dickey]

On Tue, 19 Apr 2011, Clemens Ladisch wrote:

> Christoph Ender wrote:
> > I've noticed that output of non-ASCII chars using a self-compiled ncurses 5.9 
> > (the only
> > compile-option being --enable-widec) or the MacPorts binary package of ncurses, 
> > also in
> > version 5.9, results in an errno=1.
>
> >   echo_wchar(&wcval);
> >   e2 = errno;
>
> > e2: 1
>
> > does anyone by chance have an idea what might be the cause?
>
> <http://pubs.opengroup.org/onlinepubs/009695399/functions/errno.html>:
> | The value of errno shall be defined only after a call to a function
> | for which it is explicitly stated to be set [...].  The value of
> | errno should only be examined when it is indicated to be valid by
> | a function's return value.
>
> <http://pubs.opengroup.org/onlinepubs/007908799/xcurses/echo_wchar.html>:
> | RETURN VALUE
> |     Upon successful completion, these functions return OK. Otherwise,
> |     they return ERR.
> | ERRORS
> |     No errors are defined.
>
> So, to detect errors, you should check for echo_wchar() itself returning
> ERR, and even then, the value of errno is not defined.

yes - even though the SVr4 curses would define errno's, X/Open curses
generally does not.

--
Thomas E. Dickey
http://invisible-island.net
ftp://invisible-island.net