[PATCH] [BZ #15381] Initialize wide struct info.

[Carlos O'Donell]

On 05/02/2013 01:32 PM, Ondřej Bílka wrote:
> Hi,
> For byte-oriented streams a wide data field takes undefined value.
> This patch initializes it to NULL for more deterministic behaviour.
> 
> OK for 2.18?
> 
> 	* libio/genops.c (_IO_no_init): Initialize wide struct info.
> 
> ---
>  libio/genops.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/libio/genops.c b/libio/genops.c
> index 390d8d2..18039aa 100644
> --- a/libio/genops.c
> +++ b/libio/genops.c
> @@ -643,6 +643,7 @@ _IO_no_init (fp, flags, orientation, wd, jmp)
>  {
>    _IO_old_init (fp, flags);
>    fp->_mode = orientation;
> +  fp->_wide_data = NULL;
>  #if defined _LIBC || defined _GLIBCPP_USE_WCHAR_T
>    if (orientation >= 0)
>      {
> 

Is fp->_wide_data ever used uninitialized?

Note:
libio/iofopen.c has:
83  _IO_no_init (&new_f->fp.file, 1, 0, NULL, NULL);
Which would crash at runtime if it was ever used.
It looks like the conditional that enables this code
is probably never true e.g. 
!(defined _LIBC || defined _GLIBCPP_USE_WCHAR_T)

Cheers,
Carlos.