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cout << "Hello World !" << endl;
For my very first post on stackoverflow: When are we supposed to use the htonl function? I have gone through the man page. However, I don't really understand when and how to use it.
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The htonl function can be used to convert an IPv4 address in host byte order to the IPv4 address in network byte order.
Function description: The function htonl converts an integer number from the byte order accepted on the computer into the network byte order. The function htons converts an integer short number from the byte order accepted on the computer into the network byte order.
Host to network and network to host are actually the same thing and really should be called 'change endianness if this is a little endian machine' So on a little endian machine you do net, ie be, number = htonl / ntohl (le number) and send the be number on the wire.
The htons function can be used to convert an IP port number in host byte order to the IP port number in network byte order.
Host TO Network translation. It makes sure the endian of a 32 bit data value is correct (Big endian) for network transport. ntohl -- Network TO Host -- is used by the receiver to ensure that the endian is correct for the receiver's CPU.
Keep an eye out for htons and ntohs for handling 16 bits, and out there somewhere are likely htonll and ntohll for 64 bits.
Using all of them is as simple as pass in the number you want converted and out comes the converted number. You may find that absolutely nothing has happened on some processors because their endian is already big.
uint32_t inval = 0xAABBCCDD;
uint32_t outval = htonl(inval);
Will, on most desktop hardware, result in outval being set to 0xDDCCBBAA
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