First of all I would like to thank you very much for your help.
Next, I would like to explain the scenario in which the problem takes
place. I have found a standard Unix-sockets code in a book and I have
implemented it for Win32 with no problem. Since the objective is to create
a wrapper socket API in order to work with a few OSs (Win32,
LWIP&Nucleus,...), I tried to do the same for LWIP. The structure of the
application is as follows:
Server Client
====== ======
socket
bind
listen
socket
connect <server>
accept
send
recv
socket_delete
This daytime application works in Win32 (both server and client in Win32)
with no problem. But in LWIP(server in Win32 and client in LWIP), before
the server sends the packet, the client ends the program closing the
connection. This way, the client finds nothing to receive, and the server
has no connection for when he is going to execute the send statement,
causing a send error.
At this point, I supposed that for default, sockets in LWIP were
non-blocking (is this true???), and in consequence, the lwip_recv() worked
as non blocking. That would be the reason for which it would not wait for
the server to send, and the client execution would finish before the
server send statement.
Introducing a one second sleep statement just before lwip_recv() all
worked ok.
That´s why I tried to implement a blocking recv() by calling select just
before recv(). But In spite of the 5 seconds timeval structure used as
input to this select, it did not wait. I used this select looking at the
readset in which the socket used to receive was set. At first I was afraid
that there was some kind of problem with the semaphores, dealing with the
port to Nucleus or something like that. But I have had a close look at
some other select calls, and as long as there is not a connect before,
they work perfectly waiting the timeval value etc.
I have gone into the select by debugging, and the execution changes in
sys_sem_wait_timeout(in sys.c). This function returs a 1 when it does not
wait, and a 0 if it does wait. Inside this function, the problem is in the
sys_timeout function, as it does let the sswt_cb.timeflag with a 0 value
when it does not wait, while it changes its value to 1 when it waits.
I cannot find an explanation to what happens, but actually, select does
not wait when it is called after a connect. I would be very pleased if
somebody could give me some advice.
Regards,
Borja._______________________________________________
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