[EDIT ALL]
I need it this way because I do not know ahead of time the amount of memory needed to receive one whole message. I cannot receive just a part of one message, because that will require me to totally re-do just about everything...
[edited by - zackriggle on December 23, 2002 8:43:09 PM]
pointer question
quote:Original post by micepickchar* ReadFromWinsock(...);
What''s the problem with something like that? You can get around not knowing the length of the buffer by terminating it with a NULL character like a C-style string.
EDIT: I believe that strlen() returns the number of characters in a buffer until the first NULL character. So the length of a string in a wild pointer is undefined.
There could be a NULL character anywhere if you send anything but strings. If you''d receive this:
11010011 00000000 10110111 01011001
strlen would return 1. But you would have received 4 bytes, no only two (one char + zero character). So you''d have a data loss (Imagine receiving 100MB and having a null character at the beginning...)
True. I suppose the only way around the buffer size problem is to have an argument that specifies the amount of data to read.
Author
The reason I needed the char*& function (I REMEMBER NOW) is that I need to put an entire command in one char* . I could go about doing in any of 3 ways:<br><br>– 1. The way suggested [not preferable]<br>char * x = new char [GetSizeofNextMessage()];<br>x = ReadWinsock(socket);<br><br>— 2. i can do it the way I intended: —<br>char * x;<br>ReadWinsock(socket,&x);<br><br>— 3. i can do it through a struct, as previously mentioned (now sounding very good) —<br>struct PACKET<br>{<br> char* data;<br>}<br>// function prototype<br>PACKET ReadWSock(SOCKET sck);<br><br>–> NOTE: <–<br>I think that I am going to use the struct approach. It gives me exactly what I need. I'll just not have the packet.data pointer initialized in the constructor, leaving me to KNOW that there is no memory allocated for it. The PACKETs will most likely only be filled in by the ReadWSock() function.<br>–> END NOTE <–<br><br><br>=== Note about how ~my~ messages are read in Winsock: ===<br>– There are 3 parts to a message<br>– 1 - A hex value (converted to ascii) containing the length of <br> the length of [you'll see] the data string<br>– 2 - An ?-hex long number (converted to ascii with itoa). <br> Length is specified by value #1<br>– 3 - The actual data string, X chars long [length specified by <br> #2]. This [#3] can be a char string, or a struct <br> converted to a char*<br><br>So, if I send "Hello World! This is Zach!"<br>it ends up being changed to:<br>"21AHello World! This is Zach!"<br>=========================================================<br><br><SPAN CLASS=editedby>[edited by - zackriggle on December 23, 2002 8:41:46 PM]</SPAN>
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