1. c structures and type casts in euphoria
hello all,
i am working on a project that has the need to simulate several C `struct` s
in memory. I am already using Bernie's mixedlib.e and i find it to be quite
good for what i need. I have on problem though. I need to type cast the
pointer of one of those structures created from Bernie's mixedlib.e to another
type of structure also created through that same lib.
I am simulating the `sockaddr' and `sockaddr_in' structures from C headers
files on a linux machine. As many of you probably know, you can type cast the
`sockaddr_in' to a `sockaddr' structure that many of the socket function want
as a parameter.
Is there anyway in Euphroia to type cast a structure created in memory from
Bernie's mixedlib.e to another structures created in the same way? Any help is
greatly appreciated.
CenSe,
a member of the
ak-software
development team
http://ak-software.virtualave.net/
2. Re: c structures and type casts in euphoria
On Fri, 26 May 2000 02:09:23 +0400, CenSe <cense at MAIL.RU> wrote:
>hello all,
>
>i am working on a project that has the need to simulate several C `struct`
s
>in memory. I am already using Bernie's mixedlib.e and i find it to be quite
>good for what i need. I have on problem though. I need to type cast the
>pointer of one of those structures created from Bernie's mixedlib.e to
another
>type of structure also created through that same lib.
>
>I am simulating the `sockaddr' and `sockaddr_in' structures from C headers
>files on a linux machine. As many of you probably know, you can type cast
the
>`sockaddr_in' to a `sockaddr' structure that many of the socket function
want
>as a parameter.
>
>Is there anyway in Euphroia to type cast a structure created in memory
>from Bernie's mixedlib.e to another structures created in the same way?
>Any help is greatly appreciated.
CenSe
I do not understand what you mean by casting a structure ?
Bernie
3. Re: c structures and type casts in euphoria
-----Original Message-----
>CenSe
> I do not understand what you mean by casting a structure ?
>
>Bernie
>
I am sorry, i did not explain myself properly. what i meant was that i need to
type cast a *pointer* of the `sockaddr_in' struct to a *pointer* to a struct of
type `sockaddr'.
Eg:
// the `C' function accept prototype:
int accept( int s, struct sockaddr *addr, int *addrlen ) ;
// can be used as:
* CODE BLOCK *
sockaddr *addr;
int *addrlen;
int return_val;
// assign values to addr and addrlen
return_val = accept( sock, addr, addrlen );
// or can be used with sockaddr_in like this
// where:
sockaddr_in *addr;
return_val = accept( sock, (struct sockaddr *)&addr, addrlen );
// to type cast it.
* END CODE BLOCK *
I want to be able to do this in Euphoria. Is it possible?
I hope this clarifies to you what my problem is.
CenSe,
a member of the
ak-software
development team
http://ak-software.virtualave.net/
4. Re: c structures and type casts in euphoria
On Fri, 26 May 2000 09:05:51 +0400, CenSe <cense at MAIL.RU> wrote:
>return_val = accept( sock, (struct sockaddr *)&addr, addrlen );
>
>// to type cast it.
>
CenSe:
-- This code is just to show you how to solve your cast problem
-- The code is incomplete because I do not know exactly what you are
-- doing so you can only use it as a guide
----------------------------------------------------------------------------
-
-- sin_family is address family,
-- Domain address ( AF_INET )
sequence sockaddr_in, sockaddr -- sin_port is port number
-- in network order
sockaddr_in = "sin_family:short : 1 "& -- sin_addr is Internet address
"sin_port :ushort: 1 "& -- in network order
-- In "C" sin.sin_addr.s_addr
"sin_addr :ulong : 1 "& --<<-- S_addr this is a union can be
"sin_zero :char : 8 " -- defined as 4 bytes or 2 words
-- or 1 long ( double word )
-- uchar s_b1, s_b2, s_b3, s_b4
-- ushort s_w1, s_w2
-- ulong s_dw1
-- sin_zero is 8 bytes of zero
sockaddr = "sa_family:uchar: 1 "& -- sockaddr structure NOTE*
"sa_data :char :14 " -- If you total up the bytes in
-- this structure it is the same
-- size as sockaddr_in
pointer addr, addr_in
int descriptor
addr = struc(sockaddr, HIGH) -- Create the empty structures
addr_in = struc(sockaddr_in, HIGH) --
descriptor = accept(sock, addr, sizeof(addr)) -- do the except processing
if descriptor then -- and the structure will be
-- filled in by sockets
-- copy the return addr structure to addr_in structure
mem_copy(addr_in,addr,sizeof(addr_in))
-- Now you use addr_in to access data like print the port number
? Gets(addr_in, "sin_port")
end if
----------------------------------------------------------------------------
I will respond to your other question after I have read it
Bernie
5. Re: c structures and type casts in euphoria
-----Original Message-----
>On Fri, 26 May 2000 09:05:51 +0400, CenSe <cense at MAIL.RU> wrote:
>
>>return_val = accept( sock, (struct sockaddr *)&addr, addrlen );
>>
>>// to type cast it.
>>
> CenSe:
>
>-- This code is just to show you how to solve your cast problem
>-- The code is incomplete because I do not know exactly what you are
>-- doing so you can only use it as a guide
>----------------------------------------------------------------------------
>
>I will respond to your other question after I have read it
>
>Bernie
>
>
thanks a bunch. that should help me out alot.
i was just very unsure of how `C' type casts were done in memory and that
confused me alot. thanks Bernie.
CenSe,
a member of the
ak-software
development team
http://ak-software.virtualave.net/
