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To: cs551@merlot.usc.edu
Subject: Re: cs551
Date: Fri, 29 Aug 2008 19:41:30 -0700
From: Bill Cheng <william@bourbon.usc.edu>

Someone wrote:

  > I have the following problem. When i set buf[0]=(char)0xfe and send it on
  > the other side, i can view this hex value using printf("%x",buf[0]) but how
  > can i compare this to 0xfe in order to ensure that it is an ADDR request (or
  > some other depending on buf[1]). I tried converting buf[0] to hex value
  > using itoa() but it is not in ANSI C library. What can be the workaround ?

If you want to see if buf[0] is 0xfe, you can just do:

    if (buf[0] == 0xfe) {
        ...
    }

Since MessageType is a 16-bit quantity, you can use uint16_t.
So, you can define an uint16_t variable:

    uint16_t messge_type;

Then copy 2 bytes from buf to this variable using memcpy().
Then you should call ntohs() to make your code work on both
Solaris and Linux, then you can do:

    if (message_type == 0xfe10) {
        ...
    }
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>