Re: Signal handling/zcurses

[Anthony Charles <antho.charles@xxxxxxxxx>]

Unforunately, I see no changes with this patch but with little debug, I
found out that errno is first set to 4 (EINTR), then wgetch is restarted but
failed, errno is set to 0 then my shell while loop breaks and the
script terminate.
Here's a trace :

[...]
 # refresh_screen is the function tied to USR1
+refresh_screen:28> zcurses move zmpc 0 0
 # errno from the while loop in curses.c
wgetch -- errno : 4
wgetch -- errno : 0
 # end of script, cleaning zcurses
+zmpc.sh:250> zcurses delwin zmpc
+zmpc.sh:251> zcurses delwin zmpc_status
+zmpc.sh:252> zcurses delwin zmpc_currentsong
+zmpc.sh:253> zcurses end
+zmpc.sh:257> exit 0

Strangely, if I comment my trap and kill -USR1 the script, it
terminates immediately, no debug from curses.c as if it didn't receive
the signal.


On Thu, Apr 21, 2011 at 08:47:15AM -0700, Bart Schaefer wrote:
> On Apr 21,  4:31pm, Anthony Charles wrote:
> } 
> } man 3 getch says about wgetch in portability section that it may not
> } be interrupted by signals or it may return ERR with errno set to EINTR
> } depending of the implementation and OS. In my case, on Debian it
> } seems it's the second choice :)
> 
> Try this.
> 
> Index: Src/Modules/curses.c
> ===================================================================
> --- curses.c	4 Nov 2008 04:47:53 -0000	1.4
> +++ curses.c	21 Apr 2011 15:39:05 -0000
> @@ -1070,7 +1070,11 @@
>  #endif
>  
>  #ifdef HAVE_WGET_WCH
> -    switch (wget_wch(w->win, &wi)) {
> +    while ((errno = 0), (ret = wget_wch(w->win, &wi)) == ERR) {
> +	if (errno != EINTR)
> +	    break;
> +    }
> +    switch (ret) {
>      case OK:
>  	ret = wctomb(instr, (wchar_t)wi);
>  	if (ret == 0) {
> @@ -1092,9 +1096,10 @@
>  	return 1;
>      }
>  #else
> -    ci = wgetch(w->win);
> -    if (ci == ERR)
> -	return 1;
> +    while ((errno = 0), (ci = wgetch(w->win)) == ERR) {
> +	if (errno != EINTR)
> +	    return 1;
> +    }
>      if (ci >= 256) {
>  	keypadnum = ci;
>  	*instr = '\0';
> 
> 
> -- 

-- 
Anthony CHARLES