When will I need to define HAVE_IFADDRS_H?

asked 2012-01-01 05:37:28 -0500

Hi! I am figuring out the mechanism in the roscpp package, and I found there's codes in the function determineHost() in network.cpp:

#ifdef HAVE_IFADDRS_H

...

#endif

There's a comment : fall back on interface search, which will yield an IP address

But I don't know what does it mean~

Can someone give me a brief explanation?

Thanks in advance, Ricky.

1 Answer

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answered 2012-01-01 18:01:22 -0500

The HAVE_IFADDRS_H symbol is defined by the ros build system if your system has the ifaddrs.h header; you should never have to define it yourself.

It looks like that particular chunk of code is trying to find an outward-facing IP address to use to identify the computer it's running on.

If you want more information about it, I suggest reading the man page for getifaddrs.