i know preprocessing.... i have not defined() pre-processing directive in my compiler.
in general i use #ifndef SYMBOL so.. i don't know how implement this macro... suggests? 2008/1/23, Kieran Mansley <[EMAIL PROTECTED]>: > > 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 >
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