Re: how to avoid ncurses for a small app.

[Thomas Dickey]

On Mon, Jun 19, 2006 at 08:39:25PM +0100, chinlu chinawa wrote:
> >ncurses reads a data structure from the file; it's in
> 
> >used in the read_entry.c file and (mostly(*)) 
> >documented in the term (7) manpage.
> 
> Hello Thomas,
> 
> As you said, this is a bit difficult, but really
> interesting though. I've been looking at this, and
> there are a few things I'd like to ask you.
> 
> First, given the terminfo's format described in (5)
> term, and read_entry.c, I don't undestand is why one
> can't see any big-endian/little-endian code-switching
> mechanism.

That's done with these macros in read_entry.c:

#define BYTE(p,n)       (unsigned char)((p)[n])

#define IS_NEG1(p)      ((BYTE(p,0) == 0377) && (BYTE(p,1) == 0377))
#define IS_NEG2(p)      ((BYTE(p,0) == 0376) && (BYTE(p,1) == 0377))
#define LOW_MSB(p)      (BYTE(p,0) + 256*BYTE(p,1))

Only bytes, shorts (two bytes) and strings are stored.
The first byte (lower address) of a short is always the high-order byte.

> As far as I understand it, I'm supossed to provide
> support for terminfo's database retrieval independent
> of host's target endiannes, no? 
> 
> Secondly, in term of terminfo/termios, given this
> structure from asm/termbits.h:
> 
> #define NCCS 19
> struct termios {
>         tcflag_t c_iflag; /* input mode flags */
>         tcflag_t c_oflag; /* output mode flags */
>         tcflag_t c_cflag; /* control mode flags */
>         tcflag_t c_lflag; /* local mode flags */
>         cc_t c_line;      /* line discipline */
>         cc_t c_cc[NCCS];  /* control characters */
> };
> 
> Am I supossed to fill c_cc with the respective control
> chars from the terminfo database, and then perform an
> TCSETS ioctl?

no - the ioctl fills in the data.
 
> If I'm undestanding it ok, doing it so plus setting
> the correct flags on the other structure's members,
> input might be handled as I expect despite of which
> terminfo database the TERM environment variable points
> to.
> 
> Kind Regards,
> 
>  
> 
> 
>               
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-- 
Thomas E. Dickey <address@hidden>
http://invisible-island.net
ftp://invisible-island.net