On Saturday 06 May 2006 06:18, Lan Qing wrote: > the struct in_addr have only one variable in it, is there any necessary to > define a struct like that? > why not use "typedef in_addr_t in_addr;" directly?
POSIX (the standard for UNIX software) states that: "The <netinet/in.h> header shall define the in_addr structure that includes at least the following member: in_addr_t s_addr", as you can see for youself at: http://www.opengroup.org/onlinepubs/009695399/basedefs/netinet/in.h.html So it's a structure because it has to contain AT LEAST that one member :-) But as Hannes Gredler pointed out, the result will be exactly the same wether it's a typedef or a structure: the former will be transformed by the compiler into a reference to some memory address containing 4 bytes, and the latter into a reference to some memory address containing a structure with an offset of 0 to access its first 4 bytes... -- Sébastien Raveau computer and network security student head of the hawKeye network monitor project http://hawkeye.sourceforge.net/
pgpts76JtXpsf.pgp
Description: PGP signature
