OpenEuphoria

Re: to bernie: more on mixedlib.e and other stuff

• Posted by cense <cense at MAIL.RU> Nov 21, 2000
• 406 views

On Tue, 21 Nov 2000, Bernie wrote:
>> cense:
>>   Warning I could not test this code.
>> 
>>   Because I don't know exactly how the rest of your program is coded
>>   If I understand what you are doing you don't need AssociatePtr
>>   I have tried to show you what to do in general.
>>   I hope this helps.
>> Bernie

Well im still working on that socket wrapper for linux.  I have not worked on
it in a while and just discovered this during testing.

>> -- include mixedlib.e
>> 
>> -- define the following structures outside of the function
>> -----------------------------------------------------------------
>> pointer generic_sockaddr
>>   generic_sockaddr =
>>   struc("sa_family_t:ushort:   1 "&      -- identifies format of address
>> data
>>  "sa_data    :  char: 256 ",HIGH) -- address buffer varies and can be
>>       -- greater than 14 bytes so use 256
>> 
>> -----------------------------------------------------------------
>> pointer addr_of_size_ptr -- upon RETURN contains (in bytes) address size
>>   addr_of_size_ptr = struc("length:int:1",HIGH)
>> 
>> -----------------------------------------------------------------
>> 
>> global -- assuming a socket has been established
>> function accept( int socket , pointer client, pointer client_length)
>> --
>>   int FD -- file_discriptor
>> 
>>   FD = c_func( accept_, { socket, client, client_length} )
>> 
>>   if FD < 0 then
>>     return -1 -- error condition
>>   else
>>     return FD -- return FILE DISCRIPTOR use for reading an writing/read
>> socket
>>   end if
>> --
>> end function
>> 
>> constant AF_INET = 2 --
>> pointer client1, client2
>> pointer client1_size_ptr1, client2_size_ptr1
>> 
>>   -- create the client structures
>>   client1 = dups(generic_sockaddr,HIGH) -- "C" socketaddr &client;
>>   client1_size_ptr = dups(addr_of_size_ptr,HIGH) -- "C" &client_length
>> 
>>   Sets(client1,"sa_family_t",AF_INET)   -- set the address family FORMAT
>>      -- so "C" knows what format to use
>>   int client1_FD
>>   -- get the file discriptor
>>   client1_FD = accept( socket, client1, client1_size_ptr)
>>   -- Now you can use the client1_FD to do read() or write()
>>   -- To the get the address of the client into a sequence do this:
>>   pointer client1_str_name
>>   sequence client1_seq_name
>> 
>>   -- allocate a string buffer
>>   client1_str_name = string(256)
>>   -- copy the address into the buffer this also gets rid of any garbage
>>   --   returned in the structure
>>   strncpy(client1_str_name, loc(client, "sa_data") , client1_size_ptr)
>>   -- You can use this string with any of the string functions in mixedlib.e
>>   -- or convert it to a sequence to use in Euphoria
>>   client1_seq_name = str2seq(client1_str_name)
>> 
>>   -- .... talk back and forth
>>   -- When you are DONE communicating with the client be sure to
>>   closeFD(client1_FD)
>>   free(client1)
>>   free(client1_size_ptr)
>>   free(client1_str_name)

I understand all of your code above just fine. There is one thing that i need
clarrified though. When i look at online C socket tutorials for berkley sockets
i see the author always typecast a sockaddr_in structure to sockaddr and
then pass it to accept( ) instead of just using a sockaddr struct in the first
place 

What would be the use of this?

-- 
evil, corruption and bad taste
^[cense]