How to get a list of active network interfaces in C?

Question

How to get the list of active interface in a system using C? what API or library i need to use? and Can i choose a particular interface to send data in socket programming? if yes then please give an example.

You can choose a specific interface by [binding](http://pubs.opengroup.org/onlinepubs/9699919799/functions/bind.html) it to that interfaces address. — Some programmer dude, Aug 09 '13 at 12:06
What operating system? (The answer here is more platform-specific than "unix") — Nemo, Aug 09 '13 at 14:49

score 1 · Answer 1 · answered Aug 09 '13 at 14:46

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If on Linux you might like to take look at:

int getifaddrs(struct ifaddrs **ifap);

The getifaddrs() function creates a linked list of structures describing the network interfaces of the local system, and stores the address of the first item of the list in *ifap.

answered Aug 09 '13 at 14:46

alk

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but how to choose a particular interface to send data.(i.e. eth0/wlan0 etc.) – prashant Aug 12 '13 at 02:54
@prashant: Send to the interface's address or to an address routed via the interface. – alk Aug 12 '13 at 06:34
can this "getifaddrs()" function able to detect interfaces for 3G/4G_LTE modem? it will be great if you can provide an example with output for the same. thanks! – prashant Aug 12 '13 at 10:41
@prashant: My answer links to a page containing an example on how to use `getifaddrs()`. – alk Aug 12 '13 at 10:49

score 0 · Answer 2 · edited May 23 '17 at 10:31

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You can show all the active network interfaces with ioctl() and its different flags. You can find an exemple here.

You will be able to bind your socket to a specific interface, with setsockopt(). An example can be found here.

edited May 23 '17 at 10:31

Community

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answered Aug 09 '13 at 12:15

nouney

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score 0 · Answer 3 · answered Aug 09 '13 at 22:27

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On Windows, use GetAdaptersInfo() and/or GetAdaptersAddresses().

On most POSIX-compatible systems, you can use getifaddrs().

answered Aug 09 '13 at 22:27

Remy Lebeau

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How to get a list of active network interfaces in C?

3 Answers3

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