Re: [PATCH 06/11] [C++/mingw] ser-tcp.c casts

[Simon Marchi <simon.marchi@ericsson.com>]

On 15-11-02 02:36 PM, Pedro Alves wrote:
> Fixes a few errors like these:
> 
> ../../src/gdb/ser-tcp.c: In function 'int net_open(serial*, const char*)':
> ../../src/gdb/ser-tcp.c:286:73: error: invalid conversion from 'void*' to 'char*' [-fpermissive]
>      res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);
>                                                                          ^
> 
> gdb/ChangeLog:
> 2015-11-01  Pedro Alves  <palves@redhat.com>
> 
> 	* ser-tcp.c (net_open) [USE_WIN32API]: Cast getsockopt argument to
> 	char * instead of void *.
> 	(net_read_prim): Cast recv argument to
> 	char * instead of void *.
> 	(net_write_prim): Cast send argument to char * instead of void *.
> ---
>  gdb/ser-tcp.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/gdb/ser-tcp.c b/gdb/ser-tcp.c
> index ce40b61..507e0a1 100644
> --- a/gdb/ser-tcp.c
> +++ b/gdb/ser-tcp.c
> @@ -280,10 +280,12 @@ net_open (struct serial *scb, const char *name)
>  
>      len = sizeof (err);
>      /* On Windows, the fourth parameter to getsockopt is a "char *";
> -       on UNIX systems it is generally "void *".  The cast to "void *"
> -       is OK everywhere, since in C "void *" can be implicitly
> -       converted to any pointer type.  */
> +       on UNIX systems it is generally "void *".  */
> +#ifdef USE_WIN32API
> +    res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (char *) &err, &len);
> +#else
>      res = getsockopt (scb->fd, SOL_SOCKET, SO_ERROR, (void *) &err, &len);
> +#endif

You could have done exactly the opposite of the old comment, that is cast to
(char *).  It shouldn't generate any warning in either case.  But I think that
your way is fine too.