Ntohs in windows

Note that the types involved are bit 4 byte, probably int and bit 2 byte, very likely short numbers. You'll just have to write your own. Anyway, the way these functions work is that you first decide if you're converting from host your machine's byte order or from network byte order. Improve this answer. Matthieu M. Schneider: hopefully, it just mov the argument into the return slot.

But I have one question. It seems that this relies on the integer promotions to convert data[i] to unsigned int. Shouldn't there be a cast here, e. Also, thanks for the link to Pike's essay. This gives me a warning with -Wpedantic , but the code still works. Does this array even need to be initialized, given that 32 bits are immediately copied into it? Either you explicitly turn data into a pointer like I did, or you rely on the fact that arrays decay into pointer like you did.

Show 5 more comments. Roland Illig Roland Illig I am still getting used to inclusion guards, and I guess I did not really need one here. I think that the only place I ever use lowercase ells in identifiers is with hexadecimal literals, and this is to set the suffix off from the digits.

But it always makes me wince a little, and this is a style point that I have not settled for myself yet. Does the library version of ntohl check for PDP-endianness? What about other middle-endian schemes? Some drivers may rely on that performance. This is fairly easy to do, and the result is usually smaller, faster code.

Working with CAsyncSocket , you must manage any necessary byte-order conversions yourself. Windows Sockets standardizes the "big-Endian" byte-order model and provides functions to convert between this order and others.

CArchive , however, which you use with CSocket , uses the opposite "little-Endian" order, but CArchive takes care of the details of byte-order conversions for you. By using this standard ordering in your applications, or using Windows Sockets byte-order conversion functions, you can make your code more portable. If you are writing an application that will communicate with non-MFC applications, such as an FTP server, you will probably need to manage byte-swapping yourself before you pass data to the archive object, using the Windows Sockets conversion routines ntohs , ntohl , htons , and htonl.

An example of these functions used in communicating with a non-MFC application appears later in this article. The following example shows a serialization function for a CSocket object that uses an archive.

This example presents a scenario in which you are writing a client that communicates with a non-MFC server application for which you have no access to the source code.

In this scenario, you must assume that the non-MFC server uses standard network byte order. Suppose the non-MFC server with which you plan to communicate has an established protocol for a message packet like the following:. The Message structure can have member functions, such as the Serialize member function declared above. The Serialize member function might look like this:.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. When to use ntohs function in net programming? Ask Question. Asked 8 years, 2 months ago. Active 8 years, 2 months ago. Viewed 3k times. I am learning net programming using WinPcap. Improve this question. James King James King 1, 4 4 gold badges 15 15 silver badges 23 23 bronze badges.