[ale] sendto: Invalid Argument

[Bob's ALE Mail]

Chris,

I did take a careful look at your code since I've a lot of experience with
this kind of thing.  I did not see any obvious errors.  You seem to be
correctly converting the address and port to network order (big endian as I
recall).

If you still haven't solved the problem, I suggest that you use either
printf() commands or a debugger to see what values all of your arguments
to sendto() are just before the sendto.  You should look into the DDD
debugger.  It is, IMHO, the best debugger around and the best use of
GUI I've ever seen.

Also, try putting a sleep(60) in the program just before the sendto() and
after any printf() commands and at that point use netstat to verify that
the program does have that port open and with expected values.

While it does not matter for this situation, I find that often networking
code has timing sensitivities that preclude the use of debuggers.  In other
words, by the time you react to the breakpoint the other side already has
timed out and that connection is broken.

For this reason, I find using printf() with the entire session captured by
script(I), with the results printed to paper, is the way to go.

Bob Toxen
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