I'm trying to do a multiplayer game in c, but when I send multiple package like "ARV 2\n\0" and "POS 2 0 0\n\0" from the server to the client (with send()), when I try to read them with recv(), he only found 1 package that appear to be the 2 package in 1..
So I'm asking, is that normal ? And if yes, how could I force my client to read 1 by 1 the packages ? (or my server to send them 1 by 1 if the problem come from the call send)
Thanks !
Short answer: Yes, this is normal. You are using TCP/IP, I assume. It is a byte stream protocol, there are no "packets". Network and OS on either end may combine and split the data you send in any way that fits in some buffers, or parts of network. Only thing guaranteed is, that you get the same bytes in same order.
You need to use your own packet framing. For text protocol, separate packets with, for example, '\0' bytes or newlines. Also note that network or OS may give you partial packets per single "read", so you need to handle that in your code as well. This is easiest if packet separator is single byte.
Especially for a binary protocol where there are no "unused" byte values to mark packet boundaries, you could write length of packet as binary data, then that many data bytes, then again length, data, and so on. Note that the data stream may get split to different "read" calls even in the middle of the length info as well (unless length is single byte), so you may need a few lines more of code to handle receiving split packets.
Another option would be to use UDP protocol, which indeed sends packets. But UDP packets may get lost or delivered in wrong order (and have a few other problems), so you need to handle that somehow, and this often results in you re-inventing TCP, poorly. So unless you notice TCP/IP just won't cut it, stick with that.