[Asterisk-Dev] Some select(2) usage Linux-specific

[Mark Spencer]

How about doing a macro called ast_select which resolves to select() on
linux and an inline function to do this sort of select on non-linux
systems?

Mark

On Thu, 24 Apr 2003, Thorsten Lockert wrote:

> A couple of calls to select(2) are assuming a Linux-specific side-
> effect of the passed timeval being updated with how much time was
> left in before a timeout would occur.
>
> This patch makes this work (at the expense of two more system calls)
> on many other systems.
>
> Index: channel.c
> ===================================================================
> RCS file: /usr/cvsroot/asterisk/channel.c,v
> retrieving revision 1.11
> diff -u -r1.11 channel.c
> --- channel.c	17 Apr 2003 02:52:53 -0000	1.11
> +++ channel.c	24 Apr 2003 21:46:10 -0000
> @@ -739,6 +739,9 @@
>  {
>  	/* Wait for x amount of time on a file descriptor to have input.  */
>  	struct timeval tv;
> +#ifndef __linux__
> +	struct timeval tvstart, tvend, tvlen;
> +#endif
>  	fd_set rfds, efds;
>  	int res;
>  	int x, max=-1;
> @@ -756,8 +759,23 @@
>  				max = fds[x];
>  		}
>  	}
> -	if (*ms >= 0)
> +	if (*ms >= 0)  {
> +#ifndef __linux__
> +		gettimeofday(&tvstart, NULL);
> +#endif
>  		res = select(max + 1, &rfds, NULL, &efds, &tv);
> +#ifndef __linux__
> +		gettimeofday(&tvend, NULL);
> +		timersub(&tvend, &tvstart, &tvlen);
> +		tvend.tv_sec = *ms / 1000;
> +		tvend.tv_usec = (*ms % 1000) * 1000;
> +		timersub(&tvend, &tvlen, &tv);
> +		if (tv.tv_sec < 0 || tv.tv_usec < 0) {
> +			tv.tv_sec = 0;
> +			tv.tv_usec = 0;
> +		}
> +#endif
> +	}
>  	else
>  		res = select(max + 1, &rfds, NULL, &efds, NULL);
>
> @@ -786,6 +804,9 @@
>  {
>  	/* Wait for x amount of time on a file descriptor to have input.  */
>  	struct timeval tv;
> +#ifndef __linux__
> +	struct timeval tvstart, tvend, tvlen;
> +#endif
>  	fd_set rfds, efds;
>  	int res;
>  	int x, y, max=-1;
> @@ -828,8 +849,23 @@
>  		if (fds[x] > max)
>  			max = fds[x];
>  	}
> -	if (*ms >= 0)
> +	if (*ms >= 0) {
> +#ifndef __linux__
> +		gettimeofday(&tvstart, NULL);
> +#endif
>  		res = select(max + 1, &rfds, NULL, &efds, &tv);
> +#ifndef __linux__
> +		gettimeofday(&tvend, NULL);
> +		timersub(&tvend, &tvstart, &tvlen);
> +		tvend.tv_sec = *ms / 1000;
> +		tvend.tv_usec = (*ms % 1000) * 1000;
> +		timersub(&tvend, &tvlen, &tv);
> +		if (tv.tv_sec < 0 || tv.tv_usec < 0) {
> +			tv.tv_sec = 0;
> +			tv.tv_usec = 0;
> +		}
> +#endif
> +	}
>  	else
>  		res = select(max + 1, &rfds, NULL, &efds, NULL);
>
> --
> Thorsten Lockert      | tholo at sigmasoft.com | Universe, n.:
> 2121 N. Lakeshore Dr. | tholo at openbsd.org   |         The problem.
> Chapel Hill, NC 27514 |                     |
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