On Wed, 2008-01-23 at 17:19 +0100, Piero 74 wrote: > Hi all > > in file socket .h i found this: > > #if !defined(FIONREAD) || !defined(FIONBIO) > > what is "defined" macro? have i to define in cc.h using compiler > pragma?
I suggest reading an introduction to the C preprocessor - this sort of question is probably better answered by getting the necessary background knowledge, and isn't really specific to lwIP. The line in question is saying "if whoever is using this file has already defined a lot of the constants that we need, then skip this bit, otherwise define all these constants that we need". It allows the sockets.h header to both be included where these values have been pre- defined (e.g. in an OS that has its own sockets API) or in one where they have not. Kieran _______________________________________________ lwip-users mailing list [email protected] http://lists.nongnu.org/mailman/listinfo/lwip-users
