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Re: [PATCH c++ 06/12] Fix constness problem in ioscm_make_gdb_stdio_port
- From: Doug Evans <xdje42 at gmail dot com>
- To: Simon Marchi <simon dot marchi at polymtl dot ca>
- Cc: gdb-patches at sourceware dot org
- Date: Sun, 25 Oct 2015 22:26:34 -0700
- Subject: Re: [PATCH c++ 06/12] Fix constness problem in ioscm_make_gdb_stdio_port
- Authentication-results: sourceware.org; auth=none
- References: <1445831204-16588-1-git-send-email-simon dot marchi at polymtl dot ca> <1445831204-16588-6-git-send-email-simon dot marchi at polymtl dot ca>
Simon Marchi <simon.marchi@polymtl.ca> writes:
> ioscm_make_gdb_stdio_port passes const char pointers (literal strings) to
> scm_mode_bits, which takes a non-const char pointer. Ideally, we would
> change scm_mode_bits to take a const char pointer, but it's not part of
> an API we control.
>
> Instead, it's easy enough to build the string to pass to scm_mode_bits in
> a (non-const) char array and pass that.
>
> gdb/ChangeLog:
>
> * guile/scm-ports.c (ioscm_make_gdb_stdio_port): Pass non-const
> char pointer to scm_mode_bits.
> ---
> gdb/guile/scm-ports.c | 17 +++++++++++++----
> 1 file changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/gdb/guile/scm-ports.c b/gdb/guile/scm-ports.c
> index 925f3b2..49e4fd6 100644
> --- a/gdb/guile/scm-ports.c
> +++ b/gdb/guile/scm-ports.c
> @@ -357,29 +357,38 @@ ioscm_init_stdio_buffers (SCM port, long mode_bits)
> static SCM
> ioscm_make_gdb_stdio_port (int fd)
> {
> - int is_a_tty = isatty (fd);
> const char *name;
> long mode_bits;
> SCM port;
> + char buf[3];
> +
> + memset (buf, 0, sizeof (buf));
>
> switch (fd)
> {
> case 0:
> name = input_port_name;
> - mode_bits = scm_mode_bits (is_a_tty ? "r0" : "r");
> + buf[0] = 'r';
> break;
> case 1:
> name = output_port_name;
> - mode_bits = scm_mode_bits (is_a_tty ? "w0" : "w");
> + buf[0] = 'w';
> break;
> case 2:
> name = error_port_name;
> - mode_bits = scm_mode_bits (is_a_tty ? "w0" : "w");
> + buf[0] = 'w';
> break;
> default:
> gdb_assert_not_reached ("bad stdio file descriptor");
> }
>
> + if (isatty (fd))
> + {
> + buf[1] = '0';
> + }
Community rules say to not use braces here.
Ok with that change.
> +
> + mode_bits = scm_mode_bits (buf);
> +
> port = ioscm_open_port (stdio_port_desc, mode_bits);
>
> scm_set_port_filename_x (port, gdbscm_scm_from_c_string (name));