On Fri, 2009-01-30 at 02:01 +0100, Michael 'Mickey' Lauer wrote:
> Ok, here's what I have so far:
>
> ----------------
> [CCode (cname = "fd_set", cheader_filename = "sys/select.h",
> free_function
> = "")]
> [Compact]
> public class FdSet
> {
> [CCode (cname = "FD_CLR", instance_pos=1.1)]
> public void clear (int fd);
> [CCode (cname = "FD_ISSET", instance_pos=1.1)]
> public bool isSet (int fd);
> [CCode (cname = "FD_SET", instance_pos=1.1)]
> public void set (int fd);
> [CCode (cname = "FD_ZERO")]
> public void zero ();
> }
FdSet should be a struct, not a class, we do not need reference type
semantics here. This eliminates unnecessary heap allocation. FD_ZERO
should be bound as initialization method as it just zeroes the streuct.
[CCode (cname = "fd_set", cheader_filename = "sys/select.h"]
public struct FdSet {
[CCode (cname = "FD_CLEAR")]
public FdSet ();
...
}
> I'm trying to use this like that:
> ----------------
> var readfds = new Posix.FdSet();
> var writefds = new Posix.FdSet();
> var exceptfds = new Posix.FdSet();
> Posix.TimeVal t = { 0, 0 };
> int maxfd = 10;
> int result = Posix.select( maxfd, readfds, writefds, exceptfds, t );
> ----------------
When changed to a struct, it should be used as follows (untested):
var readfds = Posix.FdSet ();
var writefds = Posix.FdSet ();
var exceptfds = Posix.FdSet ();
Posix.TimeVal t = { 0, 0 };
int maxfd = 10;
int result = Posix.select (maxfd, ref readfds, ref writefds, ref exceptfds,
ref t);
>
> The code compiles, but emits two warnings:
>
> src/multiplexer.vala:162.13-162.75: warning: result variable type
> incompatible
> with return type
This warning is currently completely harmless. Vala prints this warning
if you declare a local variable called `result' whose type is different
from the return type of the method where the variable has been declared.
The reason is that I am considering introducing an implicit `result'
variable for the return value. This might be useful in some cases, for
example, in connection with method postconditions.
Jürg
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